10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 2014

OR

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                      to                     

Commission File Number 000-14656

REPLIGEN CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	04-2729386
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
41 Seyon Street, Bldg. 1, Suite 100 Waltham, MA	02453
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (781) 250-0111

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer	¨	Accelerated filer	x
Non-accelerated filer	¨  (Do not check if a smaller reporting company)	Smaller reporting company	¨

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act.):    Yes  ¨    No  x

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of April 14, 2014.

Class	Number of Shares
Common Stock, par value $.01 per share	32,039,883

Table of Contents

		PAGE
PART I	FINANCIAL INFORMATION
Item 1.	Unaudited Condensed Consolidated Financial Statements
	Condensed Consolidated Balance Sheets as of March 31, 2014 and December 31, 2013		3
	Condensed Consolidated Statements of Comprehensive Income for the Three-Month Periods Ended March  31, 2014 and 2013		4
	Condensed Consolidated Statements of Cash Flows for the Three-Month Periods Ended March 31, 2014 and 2013		5
	Notes to Unaudited Condensed Consolidated Financial Statements		6
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations		16
Item 3.	Quantitative and Qualitative Disclosures About Market Risk		21
Item 4.	Controls and Procedures		21
PART II.	OTHER INFORMATION		22
Item 1.	Legal Proceedings		22
Item 1A.	Risk Factors		22
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds		22
Item 3.	Defaults Upon Senior Securities		22
Item 4.	Mine Safety Disclosures		22
Item 5.	Other Information		22
Item 6.	Exhibits		23
Signatures			24
Exhibit Index			25

2

REPLIGEN CORPORATION

CONDENSED CONSOLIDATED BALANCE SHEETS

(Unaudited)

	March 31, 2014			December 31, 2013
Assets
Current assets:
Cash and cash equivalents	$	49,209,621		$	39,829,653
Marketable securities		21,551,398			21,793,550
Accounts receivable, less reserve for doubtful accounts of $10,000		5,036,909			4,946,132
Royalties and other receivables		—			6,730,818
Inventories		11,441,317			11,798,638
Deferred tax asset, net		1,984			1,984
Prepaid expenses and other current assets		1,456,208			1,249,824
Total current assets		88,697,437			86,350,599
Property, plant and equipment, at cost:
Leasehold improvements		9,207,709			8,973,615
Equipment		13,939,322			13,684,954
Furniture and fixtures		2,175,604			2,116,017
Construction in progress		35,168			21,647
Total property, plant and equipment, at cost		25,357,803			24,796,233
Less: Accumulated depreciation		(12,911,214	)		(12,287,010	)
Property, plant and equipment, net		12,446,589			12,509,223
Long-term deferred tax asset, net		176,742			184,848
Long-term marketable securities		10,904,518			12,218,602
Intangible assets, net		5,915,105			6,187,632
Goodwill		994,000			994,000
Restricted cash		200,000			200,000
Total assets	$	119,334,391		$	118,644,904
Liabilities and stockholders’ equity
Current liabilities:
Accounts payable	$	1,483,447		$	1,721,459
Accrued liabilities		5,638,935			9,579,712
Total current liabilities		7,122,382			11,301,171
Other long-term liabilities		3,360,477			3,457,631
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $.01 par value, 5,000,000 shares authorized, no shares issued or outstanding		—			—
Common stock, $.01 par value, 40,000,000 shares authorized, 32,040,683 shares at March 31, 2014 and 31,925,741 shares at December 31, 2013 issued and outstanding		320,407			319,257
Additional paid-in capital		191,454,083			190,625,937
Accumulated other comprehensive income		1,857,361			1,998,330
Accumulated deficit		(84,780,319	)		(89,057,422	)
Total stockholders’ equity		108,851,532			103,886,102
Total liabilities and stockholders’ equity	$	119,334,391		$	118,644,904

The accompanying notes are an integral part of these condensed consolidated financial statements.

3

REPLIGEN CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(Unaudited)

	Three months ended March 31,
	2014			2013
Revenue:
Product revenue	$	14,334,687		$	11,934,269
Royalty and other revenue		1,991,166			4,521,724
Total revenue		16,325,853			16,455,993
Operating expenses:
Cost of product revenue		6,335,064			6,896,608
Cost of royalty revenue		—			576,857
Research and development		1,200,990			2,183,404
Selling, general and administrative		3,383,610			3,308,099
Contingent consideration – fair value adjustments		98,320			(53,974	)
Total operating expenses		11,017,984			12,910,994
Income from operations		5,307,869			3,544,999
Investment income		101,816			61,519
Interest expense		(14,085	)		(13,531	)
Other income		2,505			29,081
Income before income taxes		5,398,105			3,622,068
Income tax provision		1,121,002			1,283,832
Net income	$	4,277,103		$	2,338,236
Earnings per share:
Basic	$	0.13		$	0.07
Diluted	$	0.13		$	0.07
Weighted average shares outstanding:
Basic		31,962,843			31,240,606
Diluted		32,831,019			31,855,428
Other comprehensive income:
Unrealized gain (loss) on investments		2,184			(1,983	)
Foreign currency translation loss		(143,153	)		(256,608	)
Comprehensive income	$	4,136,134		$	2,079,645

The accompanying notes are an integral part of these condensed consolidated financial statements.

4

REPLIGEN CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

	Three months ended March 31,
	2014			2013
Cash flows from operating activities:
Net income:	$	4,277,103		$	2,338,236
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		892,407			818,920
Stock-based compensation expense		307,425			250,071
Deferred tax expense		7,566			(112,403	)
Loss (gain) on revaluation of contingent consideration		98,320			(53,974	)
Changes in assets and liabilities:
Accounts receivable		(94,064	)		(2,772,175	)
Royalties and other receivables		6,730,818			5,284,800
Inventories		331,087			872,260
Prepaid expenses and other current assets		(209,701	)		(51,472	)
Accounts payable		(236,176	)		(548,648	)
Accrued liabilities		(3,999,779	)		(1,301,152	)
Long-term liabilities		(106,216	)		(1,129,760	)
Net cash provided by operating activities		7,998,790			3,594,703
Cash flows from investing activities:
Purchases of marketable securities		(8,970,763	)		(10,538,701	)
Redemptions of marketable securities		10,529,183			5,811,555
Purchases of property, plant and equipment		(596,788	)		(322,099	)
Net cash provided by (used in) investing activities		961,632			(5,049,245	)
Cash flows from financing activities:
Exercise of stock options		497,709			956,721
Net cash provided by financing activities		497,709			956,721
Effect of exchange rate changes on cash and cash equivalents		(78,163	)		(141,985	)
Net increase (decrease) in cash and cash equivalents		9,379,968			(639,806	)
Cash and cash equivalents, beginning of period		39,829,653			29,209,821
Cash and cash equivalents, end of period	$	49,209,621		$	28,570,015
Supplemental disclosure of non-cash investing activities:
Income taxes paid	$	466,000		$	659,000

The accompanying notes are an integral part of these condensed consolidated financial statements.

5

REPLIGEN CORPORATION

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(Unaudited)

1. Basis of Presentation

The consolidated financial statements included herein have been prepared by Repligen Corporation (the “Company,” “Repligen” or “we”) in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”), for Quarterly Reports on Form 10-Q and Article 10 of Regulation S-X and do not include all of the information and footnote disclosures required by U.S. GAAP. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.

In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments, consisting of only normal, recurring adjustments necessary for a fair presentation of the financial position, results of operations and cash flows. The results of operations for the interim periods presented are not necessarily indicative of results to be expected for the entire year.

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

2. Goodwill and Intangible Assets

Goodwill

Goodwill is not amortized and is reviewed for impairment at least annually. There was no evidence of impairment to goodwill at March 31, 2014. There were no goodwill impairment charges during the three-month period ended March 31, 2014.

Intangible Assets

Intangible assets are amortized over their useful lives using the estimated economic benefit method, as applicable, and the amortization expense is recorded within selling, general and administrative expense in the Company’s statements of comprehensive income (loss). Intangible assets and their related useful lives are reviewed at least annually to determine if any adverse conditions exist that would indicate the carrying value of these assets may not be recoverable. More frequent impairment assessments are conducted if certain conditions exist, including a change in the competitive landscape, any internal decisions to pursue new or different technology strategies, a loss of a significant customer, or a significant change in the marketplace, including changes in the prices paid for our products or changes in the size of the market for our products. An impairment results if the carrying value of the asset exceeds the estimated fair value of the asset. If the estimate of an intangible asset’s remaining useful life is changed, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. The Company continues to believe that its intangible assets are recoverable at March 31, 2014.

Intangible assets consisted of the following at March 31, 2014:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,453,006	$	(581,084	)		8
Patents		240,000		(125,000	)		8
Customer relationships		6,874,961		(1,946,778	)		8
Total intangible assets	$	8,567,967	$	(2,652,862	)		8

6

Intangible assets consisted of the following at December 31, 2013:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,455,382	$	(537,589	)		8
Patents		240,000		(117,500	)		8
Customer relationships		6,897,052		(1,749,713	)		8
Total intangible assets	$	8,592,434	$	(2,404,802	)		8

Amortization expense for amortized intangible assets was approximately $248,000 for the three months ended March 31, 2014. The Company expects to record amortization expense of approximately $1,000,000 in each of the next five years related to these intangible assets.

3. Revenue Recognition

Product Sales

The Company generates revenue from the sale of products. Historically, the Company also generated revenue from licensing transactions and research and development collaborations. The Company’s product revenues are from the sale of bioprocessing products to customers in the life science and biopharmaceutical industries. Revenue related to product sales is recognized upon delivery of the product to the customer as long as there is persuasive evidence of an arrangement, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Determination of whether these criteria have been met are based on management’s judgments primarily regarding the fixed nature of the fee charged for the product delivered and the collectability of those fees. The Company has a few longstanding customers who comprise the majority of revenue and have excellent payment histories and therefore the Company does not require collateral. The Company has had no significant write-offs of uncollectible invoices in the periods presented.

At the time of sale, the Company also evaluates the need to accrue for warranty and sales returns. The supply agreements the Company has with its customers and the related purchase orders identify the terms and conditions of each sale and the price of the goods ordered. Due to the nature of the sales arrangements, inventory produced for sale is tested for quality specifications prior to shipment. Since the product is manufactured to order and in compliance with required specifications prior to shipment, the likelihood of sales return, warranty or other issues is largely diminished. Sales returns and warranty issues are infrequent and have had nominal impact on the Company’s financial statements historically.

Sale of Intellectual Property to BioMarin

In January 2014, the Company entered into an asset purchase agreement (the “Asset Purchase Agreement”) with BioMarin Pharmaceutical Inc. (“BioMarin”) to sell Repligen’s histone deacetylase inhibitor (HDACi) portfolio. Pursuant to the terms of the Asset Purchase Agreement, the Company received $2 million from BioMarin as an upfront payment on January 30, 2014. The Company is entitled to receive up to $160 million in potential future milestone payments for the development, regulatory approval and commercial sale of portfolio compounds included in the agreement. These potential milestone payments are approximately 37% related to clinical development and 63% related to initial commercial sales in specific geographies. In addition, Repligen is eligible to receive royalties on sales of therapeutic products originating from the HDACi portfolio. The royalty rates are tiered and begin in the mid-single-digits for the first HDACi portfolio product and for the first non-HDACi portfolio product with lesser amounts for any backup products developed under the Asset Purchase Agreement. Repligen’s receipt of these royalties is subject to customary offsets and deductions. There are no refund provisions in this agreement. The Company recognized $2 million of revenue in the three months ended March 31, 2014 related to the transfer of the HDACi technology under the Asset Purchase Agreement. Any milestones earned upon specified clinical development or commercial sales events or future royalty payments, under the Asset Purchase Agreement will be recognized as revenue when they are earned.

Activities under this agreement were evaluated in accordance with ASC 605-25 to determine if they represented a multiple element revenue arrangement. We identified the following deliverables in the BioMarin agreement:

• The assignment by Repligen to BioMarin of the Repligen Technology (“Repligen Know-How” and “Repligen Patents”) and the Scripps Agreement (the “Transferred Assets”);

• The transfer of certain notebooks, data, documents, biological materials (if any) and other such documents in our possession that might be useful to further development of the program (the “Technology Transfer”).

7

Two criteria must be met in order for a deliverable to be considered a separate unit of accounting. The first criterion requires that the delivered item or items have value to the customer on a stand-alone basis. The second criterion, which relates to evaluating a general right of return, is not applicable because such a provision does not exist in the Asset Purchase Agreement. The deliverables outlined above were deemed to have stand-alone value and to meet the criteria to be accounted for as separate units of accounting. Factors considered in this determination included, among other things, BioMarin’s right under the agreement to assign the Transferred Assets, whether any other vendors sell the items separately and if BioMarin could use the delivered item for its intended purpose without the receipt of the remaining deliverables. If multiple deliverables included in an arrangement are separable into different units of accounting, the multiple-element arrangements guidance addresses how to allocate the arrangement consideration to those units of accounting. The amount of allocable arrangement consideration is limited to amounts that are fixed or determinable. Arrangement consideration is allocated at the inception of the arrangement to the identified units of accounting based on their relative selling price.

We identified the arrangement consideration to allocate among the units of accounting as the $2.0 million non-refundable up-front payment and the $126,375 payment to be received upon completion of the Technology Transfer. We excluded the potential milestone payments provided for in the Asset Purchase Agreement from the arrangement consideration as they were not considered fixed or determinable at the time the Asset Purchase Agreement was signed. Because we had not sold these items on a standalone basis previously, we had no vendor-specific objective evidence of selling price. Furthermore, we did not have detailed third-party evidence of selling price, and as a result we used our best estimate of selling price for each item. In determining these prices, we considered what we would be willing to sell the items for on a standalone basis, what the market would bear for such items and what another party might charge for these items.

The up-front arrangement consideration allocated to the Transferred Assets was recognized upon execution of the Asset Purchase Agreement as the risks and rewards associated with the Transferred Assets transferred at that time. We used a discounted cash flow analysis to determine the value of the Transferred Assets. Key assumptions in the analysis included: the estimated market size for a compound targeted at Friedreich’s ataxia, the estimated remaining costs of development and time to commercialization, and the probability of successfully developing and commercializing the program. Based on this analysis, we allocated $2,115,000 to the value of the Transferred Assets. However, as the recognize revenue is limited to the non-contingent consideration received, we recognized $2,000,000, the amount of the up-front payment, as revenue in the three months ended March 31, 2014.

The estimated selling price of the Technology Transfer items was approximately $300,000 resulting in consideration allocation of approximately $11,000. However, as this item was not delivered prior to March 31, 2014, we did not recognize any revenue related to the Technology Transfer in the three months ended March 31, 2014. We expect the Technology Transfer to be delivered by June 30, 2014.

We believe that a change in the key assumptions used to determine best estimate of selling price for each of the deliverables would not have a significant effect on the allocation of arrangement consideration.

In addition to the $2 million up-front payment, we are also eligible to receive up to $160 million in potential milestone payments from BioMarin comprised of:

• Up to $60 million related to the achievement of specified clinical and regulatory milestone events; and

• Up to $100 million related to the achievement of specified commercial sales events, specifically the first commercial sale in specific territories.

We evaluated the potential milestones in accordance with ASC 605-28, which allows an entity to make an accounting policy election to recognize a payment that is contingent upon the achievement of a substantive milestone in its entirety in the period in which the milestone is achieved. This evaluation included an assessment of the risks that must be overcome to achieve the respective milestone as well as whether the achievement of the milestone was due in part to our initial clinical work, the level of effort and investment required to achieve the respective milestone and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement. There is considerable judgment involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. Milestones that are not considered substantive are recognized as earned if there are no remaining performance obligations or over the remaining period of performance, assuming all other revenue recognition criteria are met.

We believe that the $60 million of specified clinical and regulatory milestone payments are substantive. Therefore, any such milestones achieved will be recognized as revenue when earned.

Any milestones achieved upon specified commercial sales events or future royalty payments are considered contingent revenue under the Asset Purchase Agreement, and will be recognized as revenue when they are earned as there are no undelivered elements remaining and no continuing performance obligations under the arrangement.

8

Pfizer License Agreement

In December 2012, the Company entered into an exclusive worldwide licensing agreement (the “License Agreement”) with Pfizer Inc. (“Pfizer”) to advance the spinal muscular atrophy program, or SMA program. Pursuant to the terms of the License Agreement, the Company received $5 million from Pfizer as an upfront payment on January 22, 2013 and a $1 million milestone payment on September 4, 2013. The Company is entitled to receive up to $64 million in potential future payments, a portion of which may be owed to third parties. These potential payments are approximately equally divided between milestones related to clinical development and initial commercial sales in specific geographies. In addition, the Company is entitled to receive royalties on any future sales of RG3039 or any SMA compounds developed under the License Agreement. The royalty rates are tiered and begin in the high single-digits for RG3039 or lesser amounts for any backup compounds developed under the License Agreement. Repligen’s receipt of these royalties is subject to an obligation under an existing in-license agreement and other customary offsets and deductions. There are no refund provisions in this agreement. The Company recognized $4,876,000 of revenue related to the value of the license in the year ended December 31, 2012. The Company recognized $0 and $55,000 of revenue in the three months ended March 31, 2014 and 2013, respectively, related to the delivery of clinical and transition services under the License Agreement. Any milestones earned upon specified commercial sales events or future royalty payments, under the License Agreement will be recognized as revenue when they are earned.

Orencia Royalty

In April 2008, the Company settled its outstanding litigation with Bristol-Myers Squibb Company (“Bristol”) and began recognizing royalty revenue in fiscal year 2009 for Bristol’s net sales in the United States of Orencia^® which is used in the treatment of rheumatoid arthritis. The royalty agreement with Bristol provided that the Company would receive such royalty payments on sales of Orencia^® by Bristol through December 31, 2013. These royalty payments have ceased. Pursuant to the settlement with Bristol (“Bristol Settlement”), the Company recognized royalty revenue of approximately $0 and $3,846,000 for the three months ended March 31, 2014 and 2013, respectively. Revenue earned from Bristol royalties was recorded in the periods when it was earned based on royalty reports sent by Bristol to the Company. The Company has no continuing obligations to Bristol as a result of this settlement.

Pursuant to the Bristol Settlement, Repligen remitted to the University of Michigan 15% of all royalty revenue received from Bristol. Royalty expense for the three months ended March 31, 2014 and March 31, 2013 was approximately $0 and $577,000, respectively. This operating expense has been included in the Company’s Statements of Operations under the line item “Cost of royalty revenue.”

Research and Development Agreements

For the three months ended March 31, 2014 and March 31, 2013, the Company recognized approximately $0 and $621,000, respectively, of revenue from a sponsored research and development project under an agreement with the National Institutes of Health / Scripps Research Institute.

Research revenue is recognized when the expense has been incurred and services have been performed. Determination of which incurred costs qualify for reimbursement under the terms of the Company’s contractual agreements and the timing of when such costs were incurred involves the judgment of management. The Company’s calculations are based on the agreed-upon terms as stated in the arrangements. However, should the estimated calculations change or be challenged by other parties to the agreements, research revenue may be adjusted in subsequent periods. The calculations have not historically changed or been challenged, and the Company does not anticipate any significant subsequent change in its revenue related to sponsored research and development projects.

4. Accumulated Other Comprehensive Income

The following table summarizes the changes in accumulated other comprehensive income by component:

(In thousands)	Unrealized gain (loss) on investments			Foreign currency translation gain (loss)			Total
Balance at December 31, 2013	$	(5,281	)	$	2,003,611		$	1,998,330
Other comprehensive income before reclassifications		2,184			(143,153	)		(140,969	)
Amounts reclassified from accumulated other comprehensive income		—			—			—
Net current period other comprehensive income		2,184			(143,153	)		(140,969	)
Balance at March 31, 2014	$	(3,097	)	$	1,860,458		$	1,857,361

9

5. Earnings Per Share

The Company reports earnings per share in accordance with Accounting Standards Codification Topic 260, “Earnings Per Share,” which establishes standards for computing and presenting earnings per share. Basic earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of common shares and dilutive common share equivalents then outstanding. Potential common share equivalents consist of restricted stock awards and the incremental common shares issuable upon the exercise of stock options and warrants. Under the treasury stock method, unexercised “in-the-money” stock options and warrants are assumed to be exercised at the beginning of the period or at issuance, if later. The assumed proceeds are then used to purchase common shares at the average market price during the period. Share-based payment awards that entitle their holders to receive non-forfeitable dividends before vesting are considered participating securities and are considered in the calculation of basic and diluted earnings per share. Performance based option awards have been excluded from this calculation as they would not be issuable as of March 31, 2014 if that were the end of the contingency period.

Basic and diluted weighted average shares outstanding were as follows:

	Three Months Ended March 31,
	2014		2013
Weighted average common shares		31,962,843		31,240,606
Dilutive common stock options		868,176		614,822
Weighted average common shares, assuming dilution		32,831,019		31,855,428

At March 31, 2014, there were outstanding options to purchase 1,675,077 shares of the Company’s common stock at a weighted average exercise price of $5.78 per share. For the three-month period ended March 31, 2014, 207,431 options to purchase shares of the Company’s common stock were excluded from the calculation of diluted earnings per share because the exercise prices of the stock options were greater than or equal to the average price of the common shares, and were therefore anti-dilutive.

At March 31, 2013, there were outstanding options to purchase 2,231,590 shares of the Company’s common stock at a weighted average exercise price of $4.40 per share. For the three-month period ended March 31, 2013, 516,500 options to purchase shares of the Company’s common stock were excluded from the calculation of diluted earnings per share because the exercise prices of the stock options were greater than or equal to the average price of the common shares, and were therefore anti-dilutive.

6. Stock-Based Compensation

For the three months ended March 31, 2014 and 2013, the Company recorded stock-based compensation expense of $307,425 and $250,071, respectively, for share-based awards granted under the Second Amended and Restated 2001 Repligen Corporation Stock Plan (the “2001 Plan”) and the Repligen Corporation 2012 Stock Option and Incentive Plan (the “2012 Plan,” and collectively with the 2001 Plan and the 1992 Repligen Corporation Stock Option Plan, the “Plans”).

The following table presents stock-based compensation expense included in the Company’s consolidated statements of comprehensive income:

	Three Months Ended March 31,
	2014		2013
Cost of product revenue	$	26,562	$	11,664
Research and development		31,603		7,640
Selling, general and administrative		249,260		230,767
Total	$	307,425	$	250,071

The 2012 Plan allows for the granting of incentive and nonqualified options to purchase shares of common stock, restricted stock and other equity awards. Incentive options granted to employees under the Plans generally vest over a four to five-year period, with 20%-25% vesting on the first anniversary of the date of grant and the remainder vesting in equal yearly installments thereafter. Nonqualified options issued to non-employee directors and consultants under the Plans generally vest over one year. Options granted under the Plans have a maximum term of ten years from the date of grant and generally, the exercise price of the stock options equals the fair market value of the Company’s common stock on the date of grant. At March 31, 2014, options to purchase 1,675,077 shares were outstanding under the Plans. At March 31, 2014, 944,646 shares were available for future grant under the 2012 Plan.

10

The Company uses the Black-Scholes option pricing model to calculate the fair value of share-based awards on the grant date. The Company measures stock-based compensation cost at the grant date based on the estimated fair value of the award, and recognizes awards with service based vesting as expense over the employee’s requisite service period on a straight-line basis. The Company records the expense for share-based awards subject to performance-based milestone vesting over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates whether the achievement of a performance-based milestone is probable as of the reporting date. The Company has no awards that are subject to market conditions. The Company recognizes stock-based compensation expense for options that are ultimately expected to vest, and accordingly, such compensation expense has been adjusted for estimated forfeitures.

Information regarding option activity for the three months ended March 31, 2014 under the Plans is summarized below:

	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2014		1,610,988		$	5.07
Granted		181,431			11.14
Exercised		(114,942	)		4.54
Forfeited/Cancelled		(2,400	)		5.12
Options outstanding at March 31, 2014		1,675,077		$	5.78		6.98	$	12,256,703
Options exercisable at March 31, 2014		834,186		$	4.29		5.13	$	7,146,702
Vested and expected to vest at March 31, 2014 (1)		1,577,600		$	5.67		6.88	$	11,700,596

(1) This represents the number of vested options as of March 31, 2014 plus the number of unvested options expected to vest as of March 31, 2014 based on the unvested outstanding options at March 31, 2014 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between the closing price of the common stock on March 31, 2014 of $12.86 and the exercise price of each in-the-money option) that would have been received by the option holders had all option holders exercised their options on March 31, 2014.

The weighted average grant date fair value of options granted during the three months ended March 31, 2014 and 2013 was $10.58 and $3.26, respectively. The total fair value of stock options that vested during the three months ended March 31, 2014 and 2013 was approximately $343,667 and $232,617, respectively.

As of March 31, 2014, there was $3,364,170 of total unrecognized compensation cost related to unvested share-based awards. This cost is expected to be recognized over a weighted average remaining requisite service period of 3.09 years. The Company expects 743,414 unvested options to vest over the next five years.

7. Cash, Cash Equivalents and Marketable Securities

At March 31, 2014 and December 31, 2013, the Company’s investments included money market funds as well as short-term and long-term marketable securities. These marketable securities are classified as available-for-sale. Marketable securities are investments with original maturities of greater than 90 days. Long-term marketable securities are securities with maturities of greater than one year. The average remaining contractual maturity of marketable securities at March 31, 2014 is approximately 9.53 months.

Management reviewed the Company’s investments as of March 31, 2014 and December 31, 2013 and concluded that there are no securities with other than temporary impairments in the investment portfolio. The Company does not intend to sell any investments in an unrealized loss position and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases.

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Investments in money market funds and marketable securities consisted of the following at March 31, 2014:

	March 31, 2014
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	9,529,909	$	2,415	$	(120	)	$	9,532,204
Corporate and other debt securities		12,016,880		4,043		(1,729	)		12,019,194
		21,546,789		6,458		(1,849	)		21,551,398
Long-term marketable securities:
U.S. Government and agency securities		8,918,120		516		(8,279	)		8,910,357
Corporate and other debt securities		1,994,104		1,915		(1,858	)		1,994,161
		10,912,224		2,431		(10,137	)		10,904,518
Total	$	32,459,013	$	8,889	$	(11,986	)	$	32,455,916

At March 31, 2014, the Company’s investments included thirty securities in unrealized loss positions with a total unrealized loss of approximately $12,000 and a total fair market value of approximately $14,141,000. All investments with gross unrealized losses have been in unrealized loss positions for less than 12 months. The unrealized losses were caused primarily by current economic and market conditions. There was no change in the credit risk of the securities. There were no realized gains or losses on the investments for the three months ended March 31, 2014 or the year ended December 31, 2013.

Investments in money market funds and marketable securities consisted of the following at December 31, 2013:

	December 31, 2013
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	8,165,464	$	435	$	(630	)	$	8,165,269
Corporate and other debt securities		13,626,690		3,636		(2,045	)		13,628,281
		21,792,154		4,071		(2,675	)		21,793,550
Long-term marketable securities:
U.S. Government and agency securities		11,599,415		466		(7,034	)		11,592,847
Corporate and other debt securities		625,882		100		(227	)		625,755
		12,225,297		566		(7,261	)		12,218,602
Total	$	34,017,451	$	4,637	$	(9,936	)	$	34,012,152

The contractual maturities of money market funds and marketable securities at March 31, 2014 were as follows:

	Amortized Cost		Fair Value
Due in 1 year or less	$	21,546,789	$	21,551,398
Due in 1 to 2 years		10,912,224		10,904,518
	$	32,459,013	$	32,455,916

8. Fair Value Measurement

In determining the fair value of its assets and liabilities, the Company uses various valuation approaches. The Company employs a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. The fair value hierarchy is broken down into three levels based on the source of inputs as follows:

Level 1 – Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access

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Level 2	–	Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly
Level 3	–	Valuations based on inputs that are unobservable and significant to the overall fair value measurement

The availability of observable inputs can vary among the various types of financial assets and liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for financial statement disclosure purposes, the level in the fair value hierarchy within which the fair value measurement is categorized is based on the lowest level input that is significant to the overall fair value measurement.

The Company’s fixed income investments are comprised of obligations of U.S. government agencies and corporate marketable securities. These investments have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third party pricing services or other market observable data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. These observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates and other industry and economic events. At least annually, the Company validates the prices provided by third party pricing services by reviewing their pricing methods and matrices, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming that the relevant markets are active. The Company did not adjust or override any fair value measurements provided by the pricing services as of March 31, 2014.

The following fair value hierarchy table presents information about each major category of the Company’s assets measured at fair value on a recurring basis as of March 31, 2014:

	Fair value measurement at reporting date using:
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Assets:
Money market funds	$	11,953,743	$	—	$	—	$	11,953,743
U.S. Government and agency securities		10,204,720		8,237,841		—		18,442,561
Corporate and other debt securities		—		14,013,355		—		14,013,355
Total	$	22,158,463	$	22,251,196	$	—	$	44,409,659

The Company has no other assets or liabilities for which fair value measurement is either required or has been elected to be applied, other than the liabilities for contingent consideration recorded in connection with the Novozymes Acquisition and the acquisition of the assets of BioFlash Partners, LLC (“BioFlash”). The contingent consideration related to Novozymes is valued based upon an updated agreement with Novozymes Biopharma DK A/S, a company organized under the laws of Denmark (“Novozymes Denmark”). The contingent consideration related to BioFlash is valued using management’s estimates of royalties to be paid to the former shareholders of BioFlash based on sales of the acquired assets. These valuations are Level 3 valuations as the primary inputs are unobservable. Changes in the fair value of contingent consideration in the three-month period ended March 31, 2014 are primarily attributable to a $80,000 minimum royalty payment made to BioFlash, which was previously accrued, and a fair value adjustment of approximately $92,000 due to our agreement with Novozymes Denmark. The following table provides a roll forward of the fair value of the contingent consideration:

Balance at December 31, 2013	$	1,648,928
Additions		—
Payments		(80,000	)
Changes in fair value		97,777
Balance at March 31, 2014	$	1,666,705

There were no remeasurements to fair value during the three months ended March 31, 2014 of financial assets and liabilities that are not measured at fair value on a recurring basis.

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9. Inventories

Inventories relate to the Company’s bioprocessing business. The Company values inventory at cost or, if lower, fair market value, using the first-in, first-out method. The Company reviews its inventories at least quarterly and records a provision for excess and obsolete inventory based on its estimates of expected sales volume, production capacity and expiration dates of raw materials, work-in process and finished products. Expected sales volumes are determined based on supply forecasts provided by key customers for the next three to 12 months. The Company writes down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value, and inventory in excess of expected requirements to cost of product revenue. Manufacturing of bioprocessing finished goods is done to order and tested for quality specifications prior to shipment. Reserves for excess and obsolete inventory were approximately $182,000 at March 31, 2014 and $183,000 at December 31, 2013.

A change in the estimated timing or amount of demand for the Company’s products could result in additional provisions for excess inventory quantities on hand. Any significant unanticipated changes in demand or unexpected quality failures could have a significant impact on the value of inventory and reported operating results. During all periods presented in the accompanying financial statements, there have been no material adjustments related to a revised estimate of inventory valuations.

Work-in-process and finished products inventories consist of material, labor, outside processing costs and manufacturing overhead. Inventories consist of the following:

	March 31, 2014		December 31, 2013
Raw materials	$	4,224,034	$	4,557,870
Work-in-process		3,032,739		4,285,648
Finished products		4,184,544		2,955,120
Total	$	11,441,317	$	11,798,638

10. Accrued Liabilities

The Company estimates accrued liabilities by identifying services performed on the Company’s behalf, estimating the level of service performed and determining the associated cost incurred for such service as of each balance sheet date. For example, the Company would accrue for professional and consulting fees incurred with law firms, audit and accounting service providers and other third party consultants. These expenses are determined by either requesting those service providers to estimate unbilled services at each reporting date for services incurred or tracking costs incurred by service providers under fixed fee arrangements.

The Company has processes in place to estimate the appropriate amounts to record for accrued liabilities, which principally involve the applicable personnel reviewing the services provided. In the event that the Company does not identify certain costs that have begun to be incurred or the Company under or over-estimates the level of services performed or the costs of such services, the reported expenses for that period may be too low or too high. The date on which certain services commence, the level of services performed on or before a given date, and the cost of such services often require the exercise of judgment. The Company makes these judgments based upon the facts and circumstances known at the date of the financial statements.

Accrued liabilities consist of the following:

	March 31, 2014		December 31, 2013
Employee compensation	$	2,228,965	$	3,166,086
Taxes		655,703		2,324,711
Royalty and license fees		560,501		1,897,473
Contingent consideration (current portion)		1,313,145		1,195,248
Unearned revenue		—		3,341
Professional fees		402,820		385,478
VAT liabilities		—		7,591
Other accrued expenses		477,801		599,784
Total		5,638,935		9,579,712

11. Commitments and Contingencies

In March 2014, the Company entered into an amendment of its existing lease to expand the rented space from 55,694 to 75,594 square feet at 41 Seyon Street, Waltham, Massachusetts. Pursuant to the terms of the amended lease, Repligen will lease an additional 19,900 square feet (the “Expansion Space”) for a period of eight years and one month, commencing on August 1, 2014 or the date upon which the landlord’s improvements to the Expansion Space have been completed, whichever is later. The Expansion Space shall become a part of Repligen’s corporate headquarters.

The amended lease provides for additional rent expense of approximately $361,000 on an annualized basis. The amended lease also requires an increased security deposit from $200,000 to $450,000 and continues to require the Company to pay a proportionate share of certain of the landlord’s annual operating costs and real estate taxes. Future minimum rental commitments under the amended lease as of March 31, 2014 are approximately $908,000 and $1,371,000 for the remainder of the year ending December 31, 2014, and the years ending December 31, 2015, 2016, 2017 and 2018, respectively.

12. Income Taxes

For the three months ended March 31, 2014, the Company had income before taxes of approximately $5,398,000 and recorded a tax provision of approximately $1,121,000 for an effective tax rate of approximately 20.8%. This is based on an expected effective tax rate of 20.9% for the year ending December 31, 2014. For the three months ended March 31, 2013, the Company had income before taxes of approximately $3,622,000 and recorded a tax provision of $1,284,000 for an effective tax rate of approximately 35.45%. This

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was based on an expected effective tax rate of 28.21% for the year ending December 31, 2013 plus approximately $298,000 of discrete items recognized in the quarter ended March 31, 2013. The effective income tax rate is based upon the estimated income for the year and the composition of the income in different jurisdictions. The effective tax rate differs from the U.S. statutory tax rate primarily due to the lower statutory tax rate in Sweden.

The Company has net operating loss carryforwards of approximately $37,633,000 and business tax credits carryforwards of approximately $1,520,000 available to reduce future federal income taxes, if any. The net operating loss and business tax credits carryforwards will continue to expire at various dates through December 2031. Net operating loss carryforwards and available tax credits are subject to review and possible adjustment by the Internal Revenue Service and may be limited in the event of certain changes in the ownership interest of significant stockholders.

In the fourth quarter of 2012, we entered into a cumulative pre-tax income position and concluded that it was more likely than not that we would generate sufficient taxable income in 2013 based on our 2013 projections to realize the tax benefit of a portion of our deferred tax assets. We accordingly recorded a tax benefit in the fourth quarter of 2012 that included the reversal of $3,021,000 of the valuation allowance on our deferred tax assets. At December 31, 2013, as a result of the fact that we no longer receive royalty payments on Bristol’s sales of Orencia, we concluded that realization of deferred tax assets beyond December 31, 2013 was not more likely than not and we therefore maintained a valuation allowance against the majority of our remaining deferred tax assets. As of March 31, 2014, we continue to maintain a valuation allowance against the majority of our remaining deferred tax assets as we concluded that realization of deferred tax assets for the year ended December 31, 2014 and beyond was not more likely than not.

13. Segment Reporting

The Company views its operations, makes decisions regarding how to allocate resources and manages its business as one operating segment. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s principal operating segment.

The following table represents the Company’s total revenue by geographic area (based on the location of the customer):

	Three months ended March 31,
	2014			2013
United States		49	%		47	%
Sweden		32	%		39	%
United Kingdom		18	%		12	%
Other		1	%		2	%
		100	%		100	%

Revenue from significant customers as a percentage of the Company’s total revenue is as follows:

	Three months ended March 31,
	2014			2013
Upfront payment from sale of intellectual property to BioMarin		12	%		—
Orencia® Royalties from Bristol		—			24	%
Bioprocessing Customer A		40	%		38	%
Bioprocessing Customer B		22	%		12	%
Bioprocessing Customer C		14	%		15	%

Significant accounts receivable balances as a percentage of the Company’s total trade accounts receivable and royalties and other receivables balances are as follows:

	March 31, 2014			December 31, 2013
Orencia® Royalties from Bristol		—			42	%
Bioprocessing Customer A		58	%		17	%
Bioprocessing Customer B		22	%		8	%
Tenant improvement allowance due from landlord		—			15	%

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ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

Overview

We are a life sciences company that develops, manufactures and markets high-value, consumable bioprocessing products for life sciences companies and biopharmaceutical manufacturing companies worldwide. We are a world-leading manufacturer of both native and recombinant forms of Protein A, critical reagents used in biomanufacturing to separate and purify monoclonal antibodies, a type of biologic drug. We also supply several growth factor products used to increase cell culture productivity during the biomanufacturing process. In the expanding area of flexible biomanufacturing technologies, we have developed and currently market a series of OPUS (Open-Platform, User-Specified) chromatography columns for use in clinical-scale manufacturing. We generally manufacture and sell Protein A and growth factors to life sciences companies under long-term supply agreements and sell our chromatography columns, as well as media and quality test kits, directly to biopharmaceutical companies or contract manufacturing organizations. We refer to these activities as our bioprocessing business. Our manufacturing facilities are located in the United States and Sweden.

Historically, Repligen also conducted activities aimed at developing proprietary therapeutic drug candidates, often with a potential of entering into a collaboration with a larger commercial stage pharmaceutical or biotechnology company in respect of these programs. In addition, we out-licensed certain intellectual property to Bristol-Myers Squibb Company, or Bristol, from which we received royalties on Bristol’s net sales in the United States of their product Orencia^®. These royalty payments from Bristol ceased on December 31, 2013. As part of our strategic decision in 2012 to focus our efforts on our core bioprocessing business, we reduced our efforts on our clinical development programs and increased our efforts to find collaboration partners to pursue the development and, if successful, the commercialization of these drug programs. The current status of our therapeutic drug development portfolio is:

• On January 21, 2014, we entered into an asset purchase agreement (the “Asset Purchase Agreement”) with BioMarin Pharmaceutical Inc. (“BioMarin”) to advance Repligen’s histone deacetylase inhibitor (HDACi) portfolio. Pursuant to the terms of the Asset Purchase Agreement, we received $2 million from BioMarin as an upfront payment on January 30, 2014. The Company is entitled to receive up to $160 million in potential future milestone payments for the development, regulatory approval and commercial sale of portfolio compounds included in the agreement. In addition, Repligen is eligible to receive royalties on sales of therapeutic products originating from the HDACi portfolio.

• On December 28, 2012, we out-licensed our spinal muscular atrophy program, or SMA program, led by RG3039, a small molecule drug candidate in clinical development for SMA, to Pfizer Inc., or Pfizer. Pursuant to the license agreement, Pfizer assumed the majority of the costs associated with completing the required clinical trials for this program as well as obtaining U.S. Food and Drug Administration (“FDA”) approval of the respective new drug application (“NDA”). Under the license agreement, we were obligated to conduct additional activities in support of this program, which included completing the second cohort of the initial Phase I trial for RG3039 and supporting the transition of the program to Pfizer. We completed all of our obligations under the license agreement in 2013.

• Our clinical development portfolio also includes RG1068, a synthetic human hormone developed as a novel imaging agent for the improved detection of pancreatic duct abnormalities in combination with magnetic resonance imaging in patients with pancreatitis and potentially other pancreatic diseases. We submitted an NDA to the FDA and a marketing authorization application to the European Medicines Agency in the first quarter of 2012. In the second quarter of 2012, we received a complete response letter from the FDA, indicating the need for additional clinical efficacy and safety trial data. We have also received from the FDA the requirements for an additional registration study. We believe this information may be a factor in the decision by third-parties that may wish to pursue a development or commercialization agreement with us for RG1068. We expect that any additional development activities in the future will be supported by sponsors or other third parties.

Critical Accounting Policies and Estimates

A “critical accounting policy” is one which is both important to the portrayal of the Company’s financial condition and results and requires management’s most difficult, subjective or complex judgments, often as a result of the need to make estimates about the effect of matters that are inherently uncertain. For additional information, please see the discussion of our critical accounting policies in Management’s Discussion and Analysis and our significant accounting policies in Note 2 to the Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2013. There have been no changes to our critical accounting policies since December 31, 2013.

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Results of Operations

Three months ended March 31, 2014 vs. March 31, 2013

Revenues

Total revenues for the three-month periods ended March 31, 2014 and 2013 were comprised of the following:

	Three months ended March 31,				% Change
	2014		2013		2014 vs. 2013
	(in thousands, except percentages)
Bioprocessing product revenue	$	14,335	$	11,934		20	%
Royalty and other revenue		1,991		4,522		-56	%
Total revenue	$	16,326	$	16,456		-1	%

Sales of bioprocessing products for the three months ended March 31, 2014 and 2013 were $14,335,000 and $11,934,000, respectively, an increase of $2,401,000, or 20%. This increase was primarily due to increases in orders from our key bioprocessing customers. Sales of our bioprocessing products can be impacted by the timing of orders, development efforts at our customers or end-users and regulatory approvals for biologics that incorporate our products, which may result in significant quarterly fluctuations. Such quarterly fluctuations are expected, but they may not be predictive of future revenue or otherwise indicate a trend.

In the three months ended March 31, 2014, we recognized $2 million of revenue under the Asset Purchase Agreement with BioMarin Pharmaceutical Inc. (“BioMarin”) to advance Repligen’s histone deacetylase inhibitor (HDACi) portfolio.

Pursuant to the settlement with Bristol, we recognized royalty revenue of $3,846,000 for the three months ended March 31, 2013. Our royalty agreement with Bristol provided that we would receive such royalty payments on sales of Orencia^® by Bristol through December 31, 2013. These royalty payments have ceased.

For the three months ended March 31, 2013, we recognized $621,000 of revenue from a sponsored research and development project under an agreement with the National Institutes of Health / Scripps Research Institute.

Costs and operating expenses

Total costs and operating expenses for the three-month periods ended March 31, 2014 and 2013 were comprised of the following:

	Three months ended March 31,					% Change
	2014		2013			2014 vs. 2013
	(in thousands, except percentages)
Cost of product revenue	$	6,335	$	6,897			-8	%
Cost of royalty revenue		—		577			-100	%
Research and development		1,201		2,183			-45	%
Selling, general and administrative		3,384		3,308			2	%
Contingent consideration – fair value adjustments		98		(54	)		281	%
Total costs and operating expenses	$	11,018	$	12,911			-15	%

Cost of product revenue was approximately $6,335,000 and $6,897,000 for the three-month periods ended March 31, 2014 and 2013, respectively, a decrease of $562,000 or 8%. This decrease is primarily due to improved capacity utilization and increased manufacturing efficiencies. Gross margins may decline over the remainder of the 2014 based on expected production volume and shipments, and product mix.

Pursuant to the settlement with Bristol, we remitted 15% of royalty revenue received through the expiration of the settlement agreement in December 2013 to the University of Michigan. For the three-month period ended March 31, 2013, this cost of royalty revenue was approximately $577,000.

Research and development expenses were approximately $1,201,000 and $2,183,000 for the three-month periods ended March 31, 2014 and 2013, respectively, a decrease of $982,000 or 45%. This decrease is directly related to our decision in 2012 to exit therapeutic drug development and is partially offset by an increase in bioprocessing research and development expense. For the three-month periods ended March 31, 2014 and 2013, approximately $1,201,000 and $1,075,000, respectively, of our total research and development expenses were incurred on bioprocessing research and development activities. For each of the remaining quarters in 2014, we expect similar levels of research and development expenses, which relate primarily to bioprocessing product development, to those incurred in the quarter ended March 31, 2014.

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Selling, general and administrative expenses were approximately $3,384,000 and $3,308,000 for the three-month periods ended March 31, 2014 and 2013, respectively, an increase of $76,000, or 2%. This increase is primarily due to higher sales and marketing expenses. For each of the remaining quarters in 2014, we expect selling, general and administrative expenses to be moderately higher than the quarter ended March 31, 2014 as we look to expand our customer-facing activities to drive sales of our bioprocessing products.

Investment income

Investment income includes income earned on invested cash balances. Investment income was approximately $102,000 and $62,000 for the three-month periods ended March 31, 2014 and 2013, respectively. This increase of $40,000, or 65%, is primarily attributable to higher average invested cash balances.

Other income

Other income was approximately $3,000 and $29,000 for the three-month periods ended March 31, 2014 and 2013, respectively, and was primarily attributable to foreign currency gains related to our Sweden operations.

Provision for income taxes

For the three months ended March 31, 2014, we had income before taxes of approximately $5,398,000 and recorded a tax provision of approximately $1,121,000 for an effective tax rate of approximately 20.8%. This is based on an expected effective tax rate of 20.9% for the year ending December 31, 2014. The effective income tax rate is based upon the estimated income for the year and the composition of the income in different jurisdictions. The effective tax rate differs from the U.S. statutory tax rate primarily due to the lower statutory tax rate in Sweden.

Liquidity and capital resources

We have financed our operations primarily through sales of equity securities, revenues derived from product sales, research grants, and license arrangements, as well as proceeds and royalties from a litigation settlement. Our revenue for the foreseeable future will primarily be limited to our bioprocessing product revenue.

At March 31, 2014, we had cash and marketable securities of $81,666,000 compared to $73,842,000 at December 31, 2013. A deposit for leased office space of $200,000 is classified as restricted cash and is not included in cash and marketable securities totals as of March 31, 2014 or December 31, 2013.

Operating activities

For the three-month period ended March 31, 2014, our operating activities provided cash of $7,999,000 reflecting net income of $4,277,000 and non-cash charges totaling $1,306,000 including depreciation, amortization, stock-based compensation charges, deferred tax expense and fair value adjustments to contingent consideration. The remaining cash flow used in operations resulted from favorable changes in various working capital accounts.

For the three-month period ended March 31, 2013, our operating activities provided cash of $3,595,000 reflecting net income of $2,338,000 and non-cash charges totaling $903,000 including depreciation, amortization, stock-based compensation charges, deferred tax expense and fair value adjustments to contingent consideration. The remaining cash flow used in operations resulted from favorable changes in various working capital accounts.

Investing activities

We place our marketable security investments in high quality credit instruments as specified in our investment policy guidelines. Our investing activities provided $962,000 for the three-month period ended March 31, 2014, primarily due to net redemptions of marketable securities of $1,559,000 offset by $597,000 used for fixed asset additions. For the three-month period ended March 31, 2013, our investing activities consumed $5,049,000, primarily due to net purchases of marketable debt securities and $322,000 used for fixed asset additions.

Financing activities

Exercises of stock options provided cash receipts of $498,000 and $957,000 in the three-month periods ended March 31, 2014 and 2013, respectively.

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We do not currently use derivative financial instruments.

Working capital increased by approximately $6,526,000 to $81,575,000 at March 31, 2014 from $75,049,000 at December 31, 2013 due to the various changes noted above.

Our future capital requirements will depend on many factors, including the following:

• the expansion of our bioprocessing business;

• the ability to sustain sales and profits of our bioprocessing products;

• the ability to replace the Orencia royalty revenue that we ceased receiving at the end of 2013;

• the scope of and progress made in our research and development activities;

• our ability to acquire additional bioprocessing products;

• the extent of any share repurchase activity; and

• the success of any proposed financing efforts.

Absent acquisitions of additional products, product candidates or intellectual property, we believe our current cash balances are adequate to meet our cash needs for at least the next 24 months. We expect to incur continued spending related to the development and expansion of our bioprocessing product lines for the foreseeable future. Our future capital requirements may include, but are not limited to, purchases of property, plant and equipment, the acquisition of additional bioprocessing products and technologies to complement our existing manufacturing capabilities, and continued investment in our intellectual property portfolio.

We plan to continue to invest in our bioprocessing business and in key research and development activities associated with our efforts to identify and consummate development and commercialization partnerships. We actively evaluate various strategic transactions on an ongoing basis, including monetizing existing assets and licensing or acquiring complementary products, technologies or businesses that would complement our existing portfolio of development programs. We continue to seek to acquire such potential assets that may offer us the best opportunity to create value for our shareholders. In order to acquire such assets, we may need to seek additional financing to fund these investments. This may require the issuance or sale of additional equity or debt securities. The sale of additional equity may result in additional dilution to our stockholders. Should we need to secure additional financing to acquire a product, fund future investment in research and development, or meet our future liquidity requirements, we may not be able to secure such financing, or obtain such financing on favorable terms because of the volatile nature of the biotechnology marketplace.

Off-Balance Sheet Arrangements

We do not have any special purpose entities or off-balance sheet financing arrangements as of March 31, 2014.

Contractual obligations

As of March 31, 2014, we had the following fixed obligations and commitments:

	Payments Due by Period
(In thousands)	Total		Less than 1 Year		1 - 3 Years		3 - 5 Years		More than 5 Years
Operating lease obligations	$	16,449	$	2,510	$	5,260	$	3,197	$	5,482
Purchase obligations (1)		4,581		4,581		—		—		—
Contingent consideration (2)		1,666		1,306		230		130		—
Total	$	22,696	$	8,397	$	5,490	$	3,327	$	5,482

(1) Primarily represents purchase orders for the procurement of raw material for manufacturing.

(2) Represents the current estimated fair value of contingent consideration amounts relating to acquisitions. These amounts are recorded in accrued expenses and long term liabilities on our consolidated balance sheets.

Cautionary Statement Regarding Forward-Looking Statements

This Quarterly Report on Form 10-Q contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The forward-looking statements in this Quarterly Report on Form 10-Q do not constitute guarantees of future performance. Investors are cautioned that statements in this Quarterly Report on Form 10-Q which are not strictly historical statements, including, without limitation, express or implied statements or guidance regarding current or future financial performance and position, our strategic decision to focus on the growth of our bioprocessing business, management’s strategy, plans and objectives for future operations or acquisitions, clinical trials and results, litigation strategy, product candidate research, development and

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regulatory approval, selling, general and administrative expenditures, intellectual property, development and manufacturing plans, availability of materials and product and adequacy of capital resources and financing plans constitute forward-looking statements. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from those anticipated, including, without limitation, risks associated with: the success of current and future collaborative or supply relationships, including our agreement with Pfizer and BioMarin, our ability to successfully negotiate and consummate development and commercialization partnerships for our portfolio of therapeutic and diagnostic assets on acceptable terms, if at all, our ability to successfully grow our bioprocessing business, including as a result of acquisition, commercialization or partnership opportunities, the success of our clinical trials and our ability to develop and commercialize products, our ability to obtain required regulatory approvals, our compliance with all Food and Drug Administration regulations, our ability to obtain, maintain and protect intellectual property rights for our products, the risk of litigation regarding our patent and other intellectual property rights, the risk of litigation with collaborative partners, our limited sales and marketing experience and capabilities, our limited manufacturing capabilities and our dependence on third-party manufacturers and value-added resellers, our ability to hire and retain skilled personnel, the market acceptance of our products, reduced demand for our products that adversely impacts our future revenues, cash flows, results of operations and financial condition, our ability to compete with larger, better financed pharmaceutical and biotechnology companies that may develop new approaches to the treatment of our targeted diseases, our history of losses and expectation of incurring continued losses, our ability to generate future revenues, our ability to successfully integrate Repligen Sweden, including achieving manufacturing efficiencies at Repligen Sweden, our ability to raise additional capital to continue our drug development programs, our volatile stock price, the effects of our anti-takeover provisions, and the impact of the expiration on December 31, 2013 of Bristol-Meyers Squibb royalty payments based on its U.S. sales of Orencia^®. Further information on potential risk factors that could affect our financial results are included in the filings made by us from time to time with the Securities and Exchange Commission including under the section entitled “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2013.

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ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Interest Rate Risk

We have investments in money market funds and marketable securities. As a result, we are exposed to potential loss from market risks that may occur as a result of changes in interest rates, changes in credit quality of the issuer or otherwise.

We generally place our marketable security investments in high quality credit instruments, as specified in our investment policy guidelines. A hypothetical 100 basis point decrease in interest rates would result in an approximate $258,000 decrease in the fair value of our investments as of March 31, 2014. We believe, however, that the conservative nature of our investments mitigates our interest rate exposure, and our investment policy limits the amount of our credit exposure to any one issue, issuer (with the exception of U.S. agency obligations) and type of instrument. We do not expect any material loss from our marketable security investments and therefore believe that our potential interest rate exposure is limited.

Foreign Exchange Risk

Transactions by our subsidiary, Repligen Sweden, may be denominated in Swedish kronor, British pound sterling, U.S. dollars, or in Euros while the entity’s functional currency is the Swedish krona. Exchange gains or losses resulting from the translation between the transactional currency and the functional currency of Repligen Sweden are included in our consolidated statements of comprehensive income. The functional currency of the Company is U.S. dollars. Fluctuations in exchange rates may adversely affect our results of operations, financial position and cash flows. We currently do not seek to hedge this exposure to fluctuations in exchange rates.

ITEM 4. CONTROLS AND PROCEDURES

The Company’s management, with the participation of the principal executive officer and the principal financial officer, has evaluated the effectiveness of the Company’s disclosure controls and procedures (as defined in Rules 13a-15(e) or 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) as of the end of the period covered by this report. Based on such evaluation, the principal executive officer and principal financial officer have concluded that, as of the end of such period, the Company’s disclosure controls and procedures were effective in ensuring that information required to be disclosed by the Company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, on a timely basis, and is accumulated and communicated to the Company’s management, including the Company’s principal executive officer and the Company’s principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

There was no change in the Company’s internal control over financial reporting that occurred during the period covered by this Quarterly Report on Form 10-Q that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

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PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

From time to time, we may be subject to other legal proceedings and claims in the ordinary course of business. We are not currently aware of any such proceedings or claims that we believe will have, individually or in the aggregate, a material adverse effect on our business, financial condition or results of operations.

ITEM 1A. RISK FACTORS

The matters discussed in this Form 10-Q include forward-looking statements that involve risks or uncertainties. These statements are neither promises nor guarantees, but are based on various assumptions by management regarding future circumstances, over many of which Repligen has little or no control. A number of important risks and uncertainties, including those identified under the caption “Risk Factors” in Item 1A in our Annual Report on Form 10-K for the year ended December 31, 2013 and subsequent filings as well as risks and uncertainties discussed elsewhere in this Form 10-Q, could cause our actual results to differ materially from those in the forward-looking statements.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

In June 2008, the Board of Directors authorized a program to repurchase up to 1.25 million shares of our common stock to be repurchased at the discretion of management from time to time in the open market or through privately negotiated transactions. The repurchase program has no set expiration date and may be suspended or discontinued at any time. We did not repurchase any shares of common stock during the three-month period ended March 31, 2014. As of March 31, 2014, there are 657,173 shares remaining under this authorization.

ITEM 3. DEFAULTS UPON SENIOR SECURITIES

None.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

ITEM 5. OTHER INFORMATION

Lease Amendment for Space at 41 Seyon Street, Waltham, Massachusetts

On March 26, 2014, Repligen, as Tenant, entered into a Fourth Amendment to Lease with Centerpoint Acquisitions LLC, as Landlord (the “Lease Amendment”), to expand the rented space under the Lease, dated October 10, 2001, as amended (the “Lease”), from 55,694 rentable square feet on the first floor at 41 Seyon Street, Waltham, Massachusetts (the “Building”), to 75,594 rentable square feet on the first and second floors of the Building. Pursuant to the terms of the Lease Amendment, Repligen will lease an additional 19,900 rentable square feet on the first and second floors of the Building (the “Expansion Space”) for a period of eight years and one month, commencing on August 1, 2014 or the date upon which the landlord’s improvements to the Expansion Space have been completed, whichever is later. The Expansion Space shall become a part of Repligen’s corporate headquarters.

In addition to basic rent payable under the Lease and subject to annual increases, Repligen shall pay annual basic rent of $270,000 for the Expansion Space during the first lease year under the Lease Amendment, $306,000 for the Expansion Space during the second lease year under the Lease Amendment, $378,100 for the Expansion Space during the third through fifth lease year under the Lease Amendment, and $398,000 during the sixth through eighth lease year under the Lease Amendment. Under the terms of the Lease Amendment, Repligen shall also pay to the landlord an additional security deposit of $250,000. Repligen may not transfer or sublease the premises without the prior written consent of Centerpoint Acquisitions LLC, except by merger or change of control, subject to certain restrictions. The Lease Amendment contains customary representations, warranties, covenants, and termination provisions. There are no material relationships between the Company or any of its affiliates and the landlord, other than in respect of the Lease and the Lease Amendment.

The foregoing description does not purport to be complete and is qualified in its entirety by reference to the full text of the Lease Amendment, a copy of which is filed as an exhibit to this Quarterly Report, and the terms of which are incorporated herein by reference.

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ITEM 6. EXHIBITS

(a) Exhibits

Exhibit Number	Document Description
3.1	Restated Certificate of Incorporation, dated June 30, 1992 and amended September 17, 1999 (filed as Exhibit 3.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 and incorporated herein by reference). (File No. 000-14656)
3.2	Amended and Restated By-Laws (filed as Exhibit 3.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2003 and incorporated herein by reference). (File No. 000-14656)
3.3	Amendment No. 1 to the Amended and Restated By-Laws (filed as Exhibit 3.1 to Repligen Corporation’s Current Report on Form 8-K filed on December 20, 2011 and incorporated herein by reference).
3.4	Amendment No. 2 to the Amended and Restated By-Laws (filed as Exhibit 3.1 to Repligen Corporation’s Current Report on Form 8-K filed on May 25, 2012 and incorporated herein by reference).
10.1 +§	Asset Purchase Agreement, dated January 21, 2014, by and between Repligen and BioMarin Pharmaceutical Inc.
10.2	Transitional Services and Separation Agreement, dated March 18, 2014, by and between Repligen and Daniel P. Witt (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on Form 8-K filed on March 21, 2014 and incorporated herein by reference).
10.3 +	Fourth Amendment to Lease, dated March 26, 2014, by and between Repligen and Centerpoint Acquisitions LLC.
31.1 +	Rule 13a-14(a)/15d-14(a) Certification.
31.2 +	Rule 13a-14(a)/15d-14(a) Certification.
32.1 *	Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
101	The following materials from Repligen Corporation on Form 10-Q for the quarterly period ended March 31, 2014, formatted in Extensible Business Reporting Language (xBRL): (i) Consolidated Statements of Comprehensive Income, (ii) Consolidated Balance Sheets, (iii) Consolidated Statements of Cash Flows, and (iv) Notes to Consolidated Financial Statements, tagged as blocks of text.

+ Filed herewith.

* Furnished herewith.

§ Confidential treatment has been requested for portions of the exhibit and is pending clearance with the Securities and Exchange Commission.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	REPLIGEN CORPORATION
Date: May 9, 2014	By:	/S/    WALTER C. HERLIHY
		Walter C. Herlihy
		President and Chief Executive Officer
		(Principal executive officer)
		Repligen Corporation
Date: May 9, 2014	By:	/S/    WILLIAM J. KELLY
		William J. Kelly
		Chief Accounting Officer
		(Principal financial officer)
		Repligen Corporation

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EXHIBIT INDEX

Exhibit Number	Document Description
3.1	Restated Certificate of Incorporation, dated June 30, 1992 and amended September 17, 1999 (filed as Exhibit 3.1 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 1999 and incorporated herein by reference). (File No. 000-14656)
3.2	Amended and Restated By-Laws (filed as Exhibit 3.2 to Repligen Corporation’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2003 and incorporated herein by reference). (File No. 000-14656)
3.3	Amendment No. 1 to the Amended and Restated By-Laws (filed as Exhibit 3.1 to Repligen Corporation’s Current Report on Form 8-K filed on December 20, 2011 and incorporated herein by reference).
3.4	Amendment No. 2 to the Amended and Restated By-Laws (filed as Exhibit 3.1 to Repligen Corporation’s Current Report on Form 8-K filed on May 25, 2012 and incorporated herein by reference).
10.1 +§	Asset Purchase Agreement, dated January 21, 2014, by and between Repligen and BioMarin Pharmaceutical Inc.
10.2	Transitional Services and Separation Agreement, dated March 18, 2014, by and between Repligen and Daniel P. Witt (filed as Exhibit 10.1 to Repligen Corporation’s Current Report on Form 8-K filed on March 21, 2014 and incorporated herein by reference).
10.3 +	Fourth Amendment to Lease, dated March 26, 2014, by and between Repligen and Centerpoint Acquisitions LLC.
31.1 +	Rule 13a-14(a)/15d-14(a) Certification.
31.2 +	Rule 13a-14(a)/15d-14(a) Certification.
32.1 *	Certification pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
101	The following materials from Repligen Corporation on Form 10-Q for the quarterly period ended March 31, 2014, formatted in Extensible Business Reporting Language (xBRL): (i) Consolidated Statements of Comprehensive Income, (ii) Consolidated Balance Sheets, (iii) Consolidated Statements of Cash Flows, and (iv) Notes to Consolidated Financial Statements, tagged as blocks of text.

+ Filed herewith.

* Furnished herewith.

§ Confidential treatment has been requested for portions of the exhibit and is pending clearance with the Securities and Exchange Commission.

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EX-10.1

Exhibit 10.1

ASSET PURCHASE AGREEMENT

This Asset Purchase Agreement (this “Agreement”) is made and entered into as of January 21, 2014 (“Effective Date”) between BioMarin Pharmaceutical Inc., a Delaware corporation, with offices at 105 Digital Drive, Novato, CA 94949, (“BioMarin”) and Repligen Corportion, a Delaware corporation with offices at 41 Seyon Street, Building 1, Suite 100, Waltham, MA 02453 (“Repligen”). Repligen and BioMarin shall also be referred to herein individually as “Party” and collectively as “Parties”.

WHEREAS, Repligen controls certain intellectual property relating to proprietary histone deacetylase (“HDAC”) inhibitors, and has a license to certain other intellectual property related to the same subject matter under the Scripps Agreement (as defined below); and

WHEREAS, BioMarin and Repligen desire to enter into this Agreement under which BioMarin will acquire Repligen’s intellectual property assets in such HDAC inhibitors and assume Repligen’s rights and obligations under the Scripps Agreement.

Now, THEREFORE, in consideration of the foregoing and the mutual covenants and premises contained in this Agreement, the receipt and sufficiency of which are hereby expressly acknowledged, the Parties hereto agree as follows:

1. DEFINITIONS.

In this Agreement, the following words and expressions shall be construed as follows:

1.1 “Affiliate” means any person, corporation, company, partnership, joint venture, firm or other entity which controls, is controlled by or is under common control with a Party. For purposes of this Section 1.1, “control” will mean (i) in the case of corporate entities, direct or indirect ownership of at least fifty percent (50%) (or such lesser percentage that is the maximum allowed to be owned by a foreign corporation in a particular jurisdiction) of the stock or shares entitled to vote for the election of directors and (ii) in the case of non-corporate entities, direct or indirect ownership of at least fifty percent (50%) of the equity interest with the power to direct the management and policies of such non-corporate entities.

1.2 “Back-up Product” means any Product other than the [**Confidential Treatment Requested**]

1.3 “Chronic Toxicology Studies” means a GLP study with a [**Confidential Treatment Requested**]

1.4 “[**Confidential Treatment Requested**] Histone Deacetylase Inhibitor” means an inhibitor with [**Confidential Treatment Requested**] activity towards [**Confidential Treatment Requested**]

1.5 “Combination Product” means either: (a) any pharmaceutical product that consists of a Product and at least one other active ingredient that is not a Product; or (b) any combination of a Product and another pharmaceutical product that contains at least one other active ingredient that is not a Product where, in each case, such products are not formulated together but are sold together as a single product and invoiced as one product.

1.6 “Commercially Reasonable Efforts” means, in reference to a Party’s obligation to perform or achieve a specified obligation or goal with respect to a particular compound or product, efforts that are comparable in quality and scope to those efforts that are generally used by such Party to perform or achieve a comparable obligation or goal with respect to a pharmaceutical product in respect of which such Party owes no royalties or similar third party payments, which has the same regulatory requirements or status (for example, requires a prescription or is available over-the-counter), is at a comparable stage of development or product life to the relevant compound or product, and that has similar market potential to the relevant compound or product, taking into account relative safety and efficacy, product profile, the competitiveness of the marketplace, the proprietary position of the compound or product and relevant regulatory circumstances. Without limiting the foregoing, Commercially Reasonable Efforts require that a Party: [**Confidential Treatment Requested**]

1.7 “Confidential Information” has the meaning set forth in Section 9 of this Agreement.

1.8 “Control” or “Controlled” means: (i) with respect to any Information and/or Patents, the possession by a Party of the ability to grant a license or sublicense of such Information and/or Patents as provided herein, and/or (ii) with respect to proprietary materials, the possession by a Party of the ability to supply such proprietary materials to the other Party as provided herein, in each case without violating the terms of any agreement or arrangement between such Party and any third party.

1.9 “[**Confidential Treatment Requested**] Product” has the meaning set forth in Section 4.2(c).

1.10 “Dollar” means a U.S. dollar, and “$” shall be interpreted accordingly.

1.11 “EMA” means the European Medicines Agency or any successor entity.

1.12 “Executive Officer” means, with respect to Repligen, its Chief Executive Officer, and with respect to BioMarin, its Chief Executive Officer.

1.13 “EU” means the European Union, as its membership may be altered from time to time, and any successor thereto.

1.14 “FDA” means the U.S. Food and Drug Administration or any successor entity.

1.15 “First Commercial Sale” means, with respect to a particular Product in a particular country, the first arms-length sale to a Third Party of such Product in such country after Regulatory Approval has been obtained in such country. First Commercial Sale shall not include any transfer or disposition of a sample or for charitable purposes (including, without limitation, pursuant to an early access, compassionate use, named patient, indigent access or patient assistance program), or for preclinical, clinical or regulatory purposes.

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1.16 “First FA Library Compound” means the first Library Compound, other than the [**Confidential Treatment Requested**]

1.17 “First FA Library Product” means a Library Product that [**Confidential Treatment Requested**]

1.18 “First Non-FA Library Compound” means the first Library Compound, [**Confidential Treatment Requested**]. For the avoidance of doubt, the [**Confidential Treatment Requested**]

1.19 “First Non-FA Library Product” means a Library Product that contains the First Non-FA Library Compound.

1.20 “Generic Product” means, with respect to a Product in a particular country, another pharmaceutical product that: [**Confidential Treatment Requested**]

1.21 “Governmental Authority” means any multi-national, federal, state, local, municipal, provincial or other governmental authority of any nature (including any governmental division, prefecture, subdivision, department, agency, bureau, branch, office, commission, council, court or other tribunal).

1.22 “IND” means (a) an Investigational New Drug Application as defined in the FD&C Act and applicable regulations promulgated thereunder by the FDA, or (b) the equivalent application to the equivalent agency in any other regulatory jurisdiction, the filing of which is necessary to initiate or conduct clinical testing of a pharmaceutical product in humans in such jurisdiction.

1.23 “Indication” means a medically distinct and differentiable human disease, condition or disorder. For clarity, all forms of Friedreich’s Ataxia shall be considered the same Indication.

1.24 “Information” means any data, results, technology, business information and information of any type whatsoever, in any tangible or intangible form, including, without limitation, know-how, trade secrets, practices, techniques, methods, processes, inventions, improvements, developments, specifications, formulations, formulae, materials or compositions of matter of any type or kind (patentable or otherwise), software, algorithms, marketing reports, expertise, technology, test data (including pharmacological, biological, chemical, biochemical, toxicological, preclinical and clinical test data), analytical and quality control data, stability data, other study data and procedures.

1.25 “Laws” means any law, statute, rule, regulation, ordinance or other pronouncement having the effect of law of any federal, national, multinational, state, provincial, county, city or other political subdivision, domestic or foreign.

1.26 “Library Compound” means any compound [**Confidential Treatment Requested**]

3

1.27 “Library Product” means any Product containing a Library Compound as an active pharmaceutical ingredient.

1.28 “Marketing Authorization Application” or “MAA” means an application to the appropriate Regulatory Authority for approval to market a Product in any particular jurisdiction, such as an NDA in the U.S.

1.29 “NDA” means a New Drug Application, Abbreviated New Drug Application, Biologics License Application, or similar application which is required to be filed with the FDA to obtain a marketing approval of a Product in the United States.

1.30 “Net Sales” means, with respect to a particular time period, the total amounts invoiced by BioMarin, its Affiliates and their respective licensees for sales of Products made during such time period to unrelated Third Parties, less the following deductions to the extent actually allowed or incurred with respect to such sales:

(a) [**Confidential Treatment Requested**]

(b) [**Confidential Treatment Requested**]

(c) [**Confidential Treatment Requested**]

(d) [**Confidential Treatment Requested**]

(e) [**Confidential Treatment Requested**]

(f) [**Confidential Treatment Requested**]

Each of the deductions set forth above shall be reasonable and customary, and in accordance with United States Generally Accepted Accounting Principles (GAAP). Notwithstanding the foregoing, amounts billed by BioMarin, its Affiliates, or their respective licensees for the sale of Products among BioMarin, its Affiliates or their respective licensees for resale shall not be included in the computation of Net Sales hereunder. For purposes of determining Net Sales, the Products shall be deemed to be sold when shipped and a “sale” shall not include reasonable transfers or dispositions as samples or for charitable purposes (including, without limitation, pursuant to an early access, compassionate use, named patient, indigent access or patient assistance program), or transfers or dispositions for preclinical, clinical or regulatory purposes.

Net Sales for Combination Products, for the purpose of calculating BioMarin’s payment obligations hereunder, shall be determined as follows:

(i) In the event one or more Products are sold as part of a Combination Product in a particular country, and all pharmaceutical products contained in the Combination Product are sold separately in such country, the Net Sales of such Product(s), for the purposes of determining payments based on Net Sales, shall be determined by [**Confidential Treatment Requested**] in each case during the applicable Net Sales reporting period.

4

(ii) In the event one or more Products are sold as part of a Combination Product and are sold separately in finished form in such country, but the other pharmaceutical product(s) included in the Combination Product are not sold separately in finished form in such country, the Net Sales of the Product, for the purposes of determining payments based on Net Sales, shall be determined by [**Confidential Treatment Requested**] in each case during the applicable Net Sales reporting period. Under no circumstances can [**Confidential Treatment Requested**] exceed [**Confidential Treatment Requested**].

(iii) In the event that one or more of the Product(s) are not sold separately in finished form in the country, but all of the other pharmaceutical product(s) included in the Combination Product in such country are sold separately, the Net Sales of the Product, for the purposes of determining payments based on Net Sales, shall be determined by [**Confidential Treatment Requested**] in each case during the applicable Net Sales reporting period.

(iv) In the event that the Net Sales of the Product(s) when included in a Combination Product cannot be determined using the methods above, Net Sales for the purposes of determining payments based on Net Sales shall be decided by BioMarin and Repligen, acting in good faith, on the basis of the respective fair market values of the Product(s) and all other pharmaceutical products included in such Combination Product.

1.31 “Non-FA Indication” means an Indication other than Friedreich’s Ataxia.

1.32 “Patents” means (a) pending provisional and non-provisional patent applications, issued patents, utility models and designs; (b) continuations, continued prosecution applications, continuations-in-part, divisions, reissues, substitutions, confirmations, registrations, validations, re-examinations, additions, extensions, renewals, supplementary protection certificates, and term restorations of any of the foregoing and (c) any foreign equivalent or counterpart of any of the foregoing.

1.33 “Phase 1 Clinical Trial” means a human clinical trial of a Product, the principal purpose of which is to evaluate safety in healthy individuals or patients, to determine pharmacokinetic parameters and other key pharmaceutical properties of such Product (including absorption, metabolism, and elimination), or to determine the appropriate range of doses to evaluate in further clinical trials, in each case as described in 21 C.F.R. § 312.21(a), or a similar clinical study prescribed by the Regulatory Authorities in a country other than the United States.

1.34 “Phase 2 Clinical Trial” means a human clinical trial of a Product, the principal purpose of which is to evaluate the effectiveness of such Product in the target patient population, as described in 21 C.F.R. § 312.21(b), or a similar clinical study prescribed by the Regulatory Authorities in a country other than the United States. A Phase 2/3 trial shall be considered to be both a Phase 2 Clinical Trial and a Phase 3 Clinical Trial.

1.35 “Phase 3 Clinical Trial” means a human clinical trial of a Product on a sufficient number of subjects that is designed to: (a) establish that such Product is safe and efficacious for its intended use; (b) define warnings, precautions and adverse reactions that are associated with such Product in the dosage range to be prescribed; and (c) support Regulatory Approval of such

5

Product, as described in 21 C.F.R. § 312.12(c), or a similar clinical study prescribed by the Regulatory Authorities in a country other than the United States. A Phase 2/3 trial shall be considered to be both a Phase 2 Clinical Trial and a Phase 3 Clinical Trial. Any study publicly described as a pivotal study by BioMarin shall be considered a Phase 3 Clinical Trial.

1.36 “Pricing Approval” means such governmental approval, agreement, determination or decision establishing prices for a Product that can be charged or reimbursed in regulatory jurisdictions where the applicable Governmental Authorities approve or determine the price or reimbursement of pharmaceutical products.

1.37 “Product” means, on a product-by-product and country-by-country basis, a pharmaceutical formulation for use in diagnosis, treatment, prevention, or amelioration of any Indication in humans that includes or incorporates, as the active pharmaceutical ingredient, a [**Confidential Treatment Requested**] Histone Deacetylase Inhibitor that: (a) [**Confidential Treatment Requested**], (b) [**Confidential Treatment Requested**], or (c) [**Confidential Treatment Requested**]; provided, that in the event [**Confidential Treatment Requested**]. For the avoidance of doubt, any product that was licensed or acquired by BioMarin from a third party, or discovered by BioMarin as part of an independent development program without access to, reliance upon, or use of Repligen Confidential Information shall not be considered a Product.

1.38 “Regulatory Approval” means all approvals, including Pricing Approvals and government reimbursement approval (in each case if applicable), necessary for the commercial sale of a Product in a given country or regulatory jurisdiction.

1.39 “Regulatory Authority” means, in a particular country or jurisdiction, any applicable Governmental Authority involved in granting Regulatory Approval in such country or jurisdiction.

1.40 “Regulatory Exclusivity” means market exclusivity granted by a Governmental Authority designed to prevent the entry of generic product(s) onto the market, including without limitation new chemical entity exclusivity, new use or indication exclusivity, new formulation exclusivity, orphan drug exclusivity, pediatric exclusivity and 180-day generic product exclusivity, or any equivalent of the foregoing in any country in the world.

1.41 “Regulatory Materials” means regulatory applications, submissions, notifications, communications, correspondence, registrations, Regulatory Approvals or other filings made to, received from or otherwise conducted with a Regulatory Authority in order to develop, manufacture, market, sell or otherwise commercialize a Product in a particular country or jurisdiction.

1.42 “Repligen Know-How” means all Information or other materials in Repligen’s possession or Control, [**Confidential Treatment Requested**]: (a) [**Confidential Treatment Requested**]; or (b) [**Confidential Treatment Requested**].

1.43 “Repligen Patents” means: (a) [**Confidential Treatment Requested**], and (b) [**Confidential Treatment Requested**].

6

1.44 “Repligen Technology” means Repligen Know-How and Repligen Patents.

1.45 “Royalty Term” has the meaning set forth in Section 4.3(c).

1.46 “Scripps Agreement” means the License Agreement, made and entered into as of April 6, 2007, by and between Repligen and The Scripps Institute, attached hereto as Exhibit C.

1.47 “Scripps Patents” means the “Licensed Patent Rights,” as defined in Section 1.4 of the Scripps Agreement.

1.48 “Third Party” means any entity other than Repligen or BioMarin or an Affiliate of Repligen or BioMarin.

1.49 “U.S.” means the United States of America.

1.50 “Valid Claim” means, with respect to any country, a claim of (a) an issued and unexpired patent (as may be extended through supplementary protection certificate or patent term extension or the like) included within the Repligen Patents or the Scripps Patents, as the case may be, to the extent such claim has not been revoked, held invalid or unenforceable by a patent office, court or other governmental agency of competent jurisdiction in a final and non-appealable judgment (or judgment from which no appeal was taken within the allowable time period) and which claim has not been disclaimed, denied or admitted to be invalid or unenforceable through reissue, re-examination or disclaimer or otherwise or (b) a pending patent application that has not been cancelled, withdrawn or abandoned; provided, however, that if a claim of a pending patent application shall not have issued within [**Confidential Treatment Requested**] after the earliest filing date from which such claim takes priority, such claim shall not constitute a Valid Claim for the purposes of this Agreement unless and until a patent issues with such claim[**Confidential Treatment Requested**].

2. TECHNOLOGY TRANSFER.

By March 15, 2014, Repligen shall promptly transfer to BioMarin: (a) the Repligen Know-How, [**Confidential Treatment Requested**] (b) all documents and Information in Repligen’s possession or Control that are useful or necessary for BioMarin to file, prosecute, and maintain the Repligen Patents and Scripps Patents; (c) the biological materials and reagents described on Exhibit D, and (d) a complete list of [**Confidential Treatment Requested**]. For clarity, clause (a) above shall include all [**Confidential Treatment Requested**] in the [**Confidential Treatment Requested**] and [**Confidential Treatment Requested**] [**Confidential Treatment Requested**], as described in Exhibit E.

3. ASSIGNMENT OF TRANSFERRED ASSETS.

3.1 Assignment of Repligen Technology and Scripps Patents. Repligen hereby sells, assigns, transfers, conveys, and delivers to BioMarin, and BioMarin hereby purchases, accepts, and acquires from Repligen, all of Repligen’s right, title and interest in and to: (i) the Repligen Technology; and (ii) the Scripps Agreement. Within [**Confidential Treatment Requested**] of the Effective Date, Repligen shall deliver appropriate documentation to

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BioMarin evidencing such assignment, which documentation shall be in appropriate form for recording such assignments with the relevant patent offices. After the end of such [**Confidential Treatment Requested**] period, Repligen will promptly execute all other documents that BioMarin delivers to Repligen that are reasonably necessary to perfect or evidence such assignment to BioMarin. BioMarin does not assume, shall not take subject to, and shall not be liable for any liabilities or obligations of any kind or nature, whether absolute, contingent, accrued, known or unknown, of Repligen or any Affiliate of Repligen related to the ownership of the Repligen Technology and the Scripps Patents prior to the Effective Date; and such liabilities and obligations shall remain the responsibility of Repligen. Furthermore, Repligen shall continue to be responsible for all Third Party agreements and obligations not assigned to BioMarin under this Agreement, and BioMarin shall have no responsibility or liability for such agreements and obligations.

3.2 No Implied Licenses. No right or license under any Information or Patents of BioMarin, the Repligen Technology, or the Scripps Patents is granted or shall be granted by implication or estoppel. All such rights or licenses are or shall be granted only as expressly provided in this Agreement.

3.3 Exclusivity. For a period of [**Confidential Treatment Requested**] from the Effective Date, Repligen and its Affiliates shall not (directly or indirectly, and either with or without a bona fide Third Party collaborator) [**Confidential Treatment Requested**]. Upon Repligen’s or its Affiliate’s material breach of this Section 3.3, BioMarin’s payment obligations under Section 4.2 and 4.3 shall terminate.

4. PAYMENTS.

4.1 Upfront Payment. BioMarin shall pay to Repligen a non-refundable, non-creditable cash payment of Two Million Dollars ($2,000,000) within fifteen (15) days after the Effective Date. In addition, upon BioMarin’s acceptance that Repligen has completed the technology transfer required under Article 2, BioMarin shall pay Repligen $[**Confidential Treatment Requested**] to reimburse Repligen for the cost of the studies set forth in Exhibit E.

4.2 Development Milestone Payments.

(a) Any [**Confidential Treatment Requested**]. Within [**Confidential Treatment Requested**] after the first achievement by BioMarin or its Affiliate or licensee of the development milestone event set forth below with respect to [**Confidential Treatment Requested**], BioMarin shall pay to Repligen the corresponding milestone payment set forth below:

[**Confidential Treatment Requested**]

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Milestone Event	Milestone Payment
Enrollment of the first patient in the first [**Confidential Treatment Requested**] for treatment of Friedreich’s Ataxia: [**Confidential Treatment Requested**] [**Confidential Treatment Requested**] [**Confidential Treatment Requested**] [**Confidential Treatment Requested**] [**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**] $[**Confidential Treatment Requested**] $[**Confidential Treatment Requested**] $[**Confidential Treatment Requested**] $[**Confidential Treatment Requested**]

For the avoidance of doubt, the milestone payment in this Section 4.2(a) is in addition to any milestones payable in section 4.2(b) or 4.2(c).

(b) First FA Library Product. Within [**Confidential Treatment Requested**] days after the first achievement by BioMarin or its Affiliate or licensee of each development milestone event set forth below with respect to the First FA Library Product to achieve the relevant development milestone event, BioMarin shall pay to Repligen the corresponding milestone payment set forth below:

	Milestone Event	Milestone Payment
(i)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(ii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(iii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(iv)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]

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	Milestone Event	Milestone Payment
(v)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(vi)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(vii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(viii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(ix)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(x)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(xi)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]

¹  Each of the indicated milestones shall be payable [**Confidential Treatment Requested**]. Such milestone(s) shall not be payable [**Confidential Treatment Requested**]. For example, [**Confidential Treatment Requested**] then [**Confidential Treatment Requested**].

In the event that a milestone event specified in Sections 4.2(b)(ii)—(iv) is achieved prior to one or more preceding Milestone Events (as determined by the order in which the Milestone Events are specified above), then all such preceding unachieved Milestone Events will be considered achieved and the related unpaid Milestone Payments shall be due. In the event that either Milestone Event specified in Section 4.2(b)(v) or (vi) is achieved, then all preceding unachieved Milestone Events specified in Sections 4.2(b)(i)—(iv) will be considered achieved and the related unpaid Milestone Payments shall be due. In the event that the milestone event specified in 4.2(b)(viii) is achieved, then the Milestone Events in Sections 4.2(b)(i)-(iv) and (vi) shall be considered achieved and, if unpaid, the corresponding Milestone Payments shall be due. In the event that a milestone event specified in Sections 4.2(b)(x) or (xi) is achieved, then the Milestone Event in Section 4.2(b)(ix) will be considered achieved and, if unpaid, the corresponding Milestone Payment shall be due.

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Except as expressly set forth in Note 1 above, each milestone set forth in the table above shall be payable [**Confidential Treatment Requested**]. The maximum amount payable for the First FA Library Product is $[**Confidential Treatment Requested**] for Friedreich’s Ataxia and $[**Confidential Treatment Requested**] for each of two Non-FA Indications, for maximum total development milestone payments under this Section 4.2(a) of $[**Confidential Treatment Requested**].

(c) First Non-FA Library Product and Back-up Products. Within [**Confidential Treatment Requested**] days after the first achievement by BioMarin or its Affiliate or licensee of each development milestone event set forth below with respect to the First Non-FA Library Product and a Back-up Product, BioMarin shall, in each such case, pay to Repligen the corresponding milestone payment set forth below:

	Milestone Event	Milestone Payment
(i)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(ii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(iii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(iv)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(v)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(vi)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(vii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]
(viii)	[**Confidential Treatment Requested**]	$[**Confidential Treatment Requested**]

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²  In the event the first Indication is [**Confidential Treatment Requested**] and the [**Confidential Treatment Requested**] has already achieved this milestone, the milestone payment indicated in this Section 4.2(c) shall not be payable unless and until it is achieved by [**Confidential Treatment Requested**] or a [**Confidential Treatment Requested**] in a [**Confidential Treatment Requested**].

³  Such milestone(s) shall not be payable in the event the [**Confidential Treatment Requested**] has achieved the [**Confidential Treatment Requested**] in the same Indication. For example, if the [**Confidential Treatment Requested**] achieves the milestone in [**Confidential Treatment Requested**], and the [**Confidential Treatment Requested**] later achieves the milestone in [**Confidential Treatment Requested**] in the same Indication, then no payment shall be due for the milestone in [**Confidential Treatment Requested**].

With respect to the First FA Library Product or a given Back-up Product:

(1) in the event that a milestone event [**Confidential Treatment Requested**] is achieved prior to one or more preceding Milestone Events (as determined by the order in which the Milestone Events are specified above), then all such preceding unachieved Milestone Events will be considered achieved and the related unpaid Milestone Payments shall be due;

(2) in the event that either Milestone Event [**Confidential Treatment Requested**] is achieved, then all preceding unachieved Milestone Events specified in Sections 4.2(c)(i)—(iii) will be considered achieved and the related unpaid Milestone Payments shall be due; and

(3) in the event that a milestone event specified in [**Confidential Treatment Requested**] is achieved, then the Milestone Event in [**Confidential Treatment Requested**] will be considered achieved and, if unpaid, the corresponding Milestone Payment shall be due.

Each milestone set forth in the table above shall be payable [**Confidential Treatment Requested**], regardless of how many Products achieve such milestone and regardless of whether the same Product achieves such milestone more than once. The maximum amount payable under this Section 4.2(c) for a single Product (i.e. either the First Non-FA Library Product or a Back-up Product) is $[**Confidential Treatment Requested**] for [**Confidential Treatment Requested**] Indication and $[**Confidential Treatment Requested**] for [**Confidential Treatment Requested**] Indication for a single Product, for maximum total development milestone payments under this Section 4.2(c) of $[**Confidential Treatment Requested**].

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In the event a Back-Up Product is a “Product” [**Confidential Treatment Requested**] (a “[**Confidential Treatment Requested**] Product”), then the milestones payable under this section for such Back-Up Product shall [**Confidential Treatment Requested**] as follows:

Enrollment of the first patient in [**Confidential Treatment Requested**] occurs:	Percent of applicable milestone payable
[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%

4.3 Royalty Payments.

(a) First FA Library Product and First Non-FA Library Product. For the First FA Library Product and the First Non-FA Library Product, BioMarin shall pay to Repligen non-refundable, non-creditable royalty payments during the applicable Royalty Term, as calculated (i) by multiplying the applicable royalty rate set forth below by the corresponding amount of incremental Net Sales of such Products in the applicable calendar year and (ii) by subsequently making all applicable adjustments in accordance with Section 4.3(d).

Annual Net Sales	Royalty Rate
For that portion of annual Net Sales that is less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%

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(b) Back-up Products. For Back-up Products, BioMarin shall pay to Repligen non-refundable, non-creditable royalty payments during the applicable Royalty Term, as calculated (i) by multiplying the applicable royalty rate set forth below by the corresponding amount of incremental Net Sales of such Products in the applicable calendar year and (ii) by subsequently making all applicable adjustments in accordance with Section 4.3(d).

Annual Net Sales of Back-up Products	Royalty Rate for Back-up Products other than Derived Products	Royalty Rate for Derived Products4
For that portion of annual Net Sales that is less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**] but less than or equal to $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%	[**Confidential Treatment Requested**]%
For that portion of annual Net Sales that is greater than $[**Confidential Treatment Requested**]	[**Confidential Treatment Requested**]%	[**Confidential Treatment Requested**]%

⁴  Royalties shall only be payable for [**Confidential Treatment Requested**] Products for which enrollment of the first patient in [**Confidential Treatment Requested**] occurs prior to [**Confidential Treatment Requested**]. For any [**Confidential Treatment Requested**] Product for which enrollment of the first patient in [**Confidential Treatment Requested**] occurs on or after [**Confidential Treatment Requested**], the royalty rate will be [**Confidential Treatment Requested**] percent ([**Confidential Treatment Requested**]%). [**Confidential Treatment Requested**]

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(c) Royalty Term. Royalties shall be paid under this Section 4.3, on a country-by-country and Product-by-Product basis, during the period of time beginning from the First Commercial Sale of such Product in such country until the later of: (i) the expiration of Regulatory Exclusivity for such Product in such country; (ii) the expiration of the last-to-expire Valid Claim claiming such Product in such country; or (iii) [**Confidential Treatment Requested**] (the “Royalty Term”). In the event that, in a given jurisdiction, there is no Valid Claim claiming a given Product [**Confidential Treatment Requested**] but [**Confidential Treatment Requested**], then the royalty payable by BioMarin shall be [**Confidential Treatment Requested**] percent ([**Confidential Treatment Requested**]%) of the royalty rate otherwise applicable under Section 4.3(a) or Section 4.3(b).

(d) Royalty Adjustments. To the extent applicable, BioMarin may apply any and all of the following adjustments to the royalty payments due to Repligen under this Section 4.3(d), and these deductions shall apply in addition to any royalty deduction applied under Section 4.3(c)(iii).

(i) Third Party Intellectual Property. If BioMarin, in its reasonable judgment, is required to obtain a license from any Third Party under any intellectual property owned or controlled by such Third Party that would be infringed or misappropriated by the importation, sale, manufacture or use of a Product, then, the royalty payment that would otherwise be due pursuant to this Section 4.3 shall be reduced by [**Confidential Treatment Requested**] percent ([**Confidential Treatment Requested**]%) of the amount of the royalty payments made by BioMarin to such Third Party; provided, however, that the royalty payment that would otherwise be due pursuant to this Section 4.3 with respect to a particular calendar quarter [**Confidential Treatment Requested**]. BioMarin may carry forward to a subsequent calendar quarter any amounts that it was not able to deduct as a result of the foregoing proviso.

(ii) Generic Product. During the portion of the applicable Royalty Term in a particular country where there are one or more products being sold in such country that are Generic Products with respect to a particular Product, then the royalty payment that would otherwise be due pursuant to this Section 4.3 with respect to such Product in such country shall be reduced by [**Confidential Treatment Requested**] percent ([**Confidential Treatment Requested**]%). [**Confidential Treatment Requested**]

(iii) Royalty [**Confidential Treatment Requested**]. BioMarin may [**Confidential Treatment Requested**], applicable to [**Confidential Treatment Requested**] and [**Confidential Treatment Requested**], by [**Confidential Treatment Requested**], subject to [**Confidential Treatment Requested**], provided such [**Confidential Treatment Requested**] shall not [**Confidential Treatment Requested**] above, by: (a) [**Confidential Treatment Requested**], or (b) [**Confidential Treatment Requested**]. Only if BioMarin first exercises [**Confidential Treatment Requested**], then BioMarin may [**Confidential Treatment Requested**], subject to [**Confidential Treatment Requested**], by: (a) [**Confidential Treatment Requested**], or (b) [**Confidential Treatment Requested**]. BioMarin may [**Confidential Treatment Requested**], subject to [**Confidential Treatment Requested**], provided such [**Confidential Treatment Requested**], by [**Confidential Treatment Requested**] per [**Confidential Treatment Requested**], or [**Confidential Treatment Requested**] per [**Confidential Treatment Requested**].

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4.4 Royalty Reports and Payments. Within [**Confidential Treatment Requested**] days following the end of each calendar quarter, commencing with the calendar quarter in which the First Commercial Sale of any Product occurs, BioMarin shall provide Repligen with a report containing the following information for the applicable calendar quarter, on a country-by-country and Product-by-Product basis: [**Confidential Treatment Requested**]. Concurrent with the delivery of the applicable quarterly report, BioMarin shall pay in Dollars all amounts due to Repligen pursuant to Section 4.3 with respect to Net Sales by BioMarin, its Affiliates and their respective sublicensees for such calendar quarter.

4.5 Obligations to Third Parties. BioMarin shall be responsible for all [**Confidential Treatment Requested**]. BioMarin acknowledges that anything herein to the contrary notwithstanding, the rights granted to BioMarin to and under the Scripps Agreement, including rights to the Scripps Patents and any other intellectual property of Scripps, are in all cases subject to the terms, conditions and limitations set forth in the Scripps Agreement.

4.6 Payment Method. All payments due to Repligen hereunder shall be made in Dollars by wire transfer of immediately available funds into an account designated by Repligen.

4.7 Records; Audits. BioMarin and its Affiliates and sublicensees will maintain complete and accurate records in sufficient detail to permit Repligen to confirm the accuracy of the calculation of royalty payments and the achievement of milestone events. Upon reasonable prior notice, such records shall be available during regular business hours for a period of [**Confidential Treatment Requested**] years from the end of the calendar year to which they pertain for examination, and not more often than [**Confidential Treatment Requested**] each calendar year, by an independent certified public accountant selected by Repligen and reasonably acceptable to BioMarin, for the sole purpose of verifying the accuracy of the previously unaudited financial reports furnished by BioMarin pursuant to this Agreement. Any such auditor shall not disclose BioMarin’s Confidential Information, except to the extent such disclosure is necessary to verify the accuracy of the financial reports furnished by BioMarin or the amount of payments due by BioMarin to Repligen under this Agreement. Any amounts shown to be owed but unpaid shall be paid within [**Confidential Treatment Requested**] days from the accountant’s report. Repligen shall bear the full cost of such audit unless such audit discloses an underpayment by the BioMarin of more than [**Confidential Treatment Requested**] percent ([**Confidential Treatment Requested**]%) of the amount due, in which case BioMarin shall bear the reasonable cost of such audit.

4.8 Taxes.

(a) Taxes on Income. Each Party shall be solely responsible for the payment of all taxes imposed on its share of income arising directly or indirectly from the efforts of the Parties under this Agreement.

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(b) Tax Cooperation. The Parties agree to cooperate with one another and use reasonable efforts to reduce or eliminate tax withholding or similar obligations in respect of royalties, milestone payments, and other payments made by BioMarin to Repligen under this Agreement. To the extent BioMarin is required to deduct and withhold taxes on any payment to Repligen, BioMarin shall pay the amounts of such taxes to the proper Governmental Authority in a timely manner and promptly transmit to Repligen an official tax certificate or other evidence of such withholding sufficient to enable Repligen to claim such payment of taxes. Repligen shall provide BioMarin any tax forms that may be reasonably necessary in order for BioMarin not to withhold tax or to withhold tax at a reduced rate under an applicable bilateral income tax treaty. Each Party shall provide the other with reasonable assistance to enable the recovery, as permitted by applicable Laws, of withholding taxes, value added taxes, or similar obligations resulting from payments made under this Agreement, such recovery to be for the benefit of the Party bearing such withholding tax or value added tax.

5. REPRESENTATIONS AND WARRANTIES.

5.1 Each Party hereby represents and warrants to the other Party as follows:

(a) It is a company or corporation duly organized, validly existing, and in good standing under the laws of the jurisdiction in which it is incorporated, and has full corporate power and authority and the legal right to own and operate its property and assets and to carry on its business as it is now being conducted and as contemplated in this Agreement;

(b) It has the corporate power and authority and the legal right to enter into this Agreement and perform its obligations hereunder; (ii) it has taken all necessary corporate action on its part required to authorize the execution and delivery of the Agreement and the performance of its obligations hereunder; and (iii) the Agreement has been duly executed and delivered on behalf of such Party, and constitutes a legal, valid, and binding obligation of such Party that is enforceable against it in accordance with its terms; and

(c) It is not a party to any agreement that would prevent it from granting the rights granted to the other Party under this Agreement or performing its obligations under the Agreement.

5.2 Repligen hereby represents, warrants and covenants that:

(a) It has sufficient legal or beneficial title, ownership or license, free and clear from any mortgages, pledges, liens, security interests, conditional and installment sale agreements, encumbrances, charges or claims of any kind, of the Repligen Technology and the Scripps Patents to grant the assignments to BioMarin as purported to be granted pursuant to this Agreement. As of the Effective Date, Repligen is the sole owner of all right, title and interest in and to (free and clear from any mortgages, pledges, liens, security interests, conditional and installment sale agreements, encumbrances, charges or claims of any kind) of the Repligen Technology identified in Exhibit G (“Owned Repligen Technology”; all remaining Repligen Technology is “Licensed Repligen Technology”).

(b) It has not received any written notice from any Third Party asserting or alleging that any research or development of the Products by Repligen prior to the Effective Date infringed or misappropriated the intellectual property rights (including any trade secrets) of such Third Party. The Repligen Technology and the Scripps Patents existing as of the Effective Date were not obtained in violation of any contractual or fiduciary obligation owed by Repligen or its employees or agents to any Third Party.

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(c) To Repligen’s knowledge, (i) the research, development, manufacture, use and sale after the Effective Date of Products can be carried out in the manner reasonably contemplated as of the Effective Date, and (ii) the research, development, manufacture and use prior to the Effective Date of Products by or on behalf of Repligen has been carried out, without infringing any published patent applications (evaluating such patent applications as though they were issued with the claims as published as of the Effective Date) or issued patents owned or controlled by a Third Party.

(d) There are no pending, and to Repligen’s knowledge no threatened, adverse actions, suits or proceedings against Repligen involving Repligen Technology, Scripps Patents, or the Products.

(e) To Repligen’s knowledge, there are no activities by Third Parties that would constitute infringement or misappropriation of the Repligen Technology or Scripps Patents existing as of the Effective Date (in the case of pending claims, evaluating them as if issued as of the Effective Date).

(f) It has not conveyed or licensed, and will not attempt to convey or license after the Effective Date, to a Third Party any right, title, or interest in, to or under any Repligen Technology or Scripps Patents (including to the Scripps Agreement) which conflicts with any rights and licenses granted to BioMarin under this Agreement.

(g) The Scripps Agreement is in full force and effect in accordance with its terms, and Repligen is not in breach of such agreement and has not received notice from any party to the Scripps Agreement that it is in breach of any such agreement.

(h) To Repligen’s knowledge, no person, other than former or current employees of Repligen who are obligated in writing to assign his/her inventions to Repligen, is an inventor of any of the inventions within the Owned Repligen Technology.

(i) The development of Products has been conducted prior to the Effective Date by Repligen and its Affiliates and, to the knowledge of Repligen, its independent contractors, in compliance in all material respects with all applicable Laws, including all public health, environmental, and safety provisions thereof.

(j) It has disclosed to BioMarin all material information known to Repligen with respect to the safety and efficacy of Products as determined from nonclinical or clinical studies.

(k) Exhibit B sets forth all of the Patents Controlled by Repligen or its Affiliates as of the Effective Date that relate to Repligen’s HDAC inhibitor program, and, other than such Patents, there are no inventions described in an invention disclosure form or draft patent application relating to HDAC inhibitors in Repligen’s or its Affiliates’ Control.

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(l) All patent applications within the Repligen Patents are still pending and all issued Patents within the Repligen Patents are in good standing and have not been abandoned.

(m) The Repligen Patents are not the subject of any interference, opposition, reexamination, reissue or similar proceeding.

6. DILIGENCE.

6.1 BioMarin Diligence Obligations. BioMarin shall, directly or indirectly through one or more sublicensees or assignees, use Commercially Reasonable Efforts to commercialize [**Confidential Treatment Requested**]. BioMarin shall provide written annual reports within 30 days of each anniversary of the Effective Date to Repligen detailing progress made with Products during such preceding annual period including [**Confidential Treatment Requested**]. For clarity, BioMarin shall have no obligation to commercialize [**Confidential Treatment Requested**]. BioMarin’s obligations under this Section 6.1 shall terminate upon the later of: (a) expiration of the last Valid Claim within the Repligen Patents, and (b) the tenth (10^th) anniversary of the Effective Date.

6.2 Impact of Failed Diligence. If BioMarin is in breach of Section 6.1 and fails to cure such breach within [**Confidential Treatment Requested**] of written notice by Repligen detailing the nature of such breach, then: (a) [**Confidential Treatment Requested**], and (b) [**Confidential Treatment Requested**]. Within [**Confidential Treatment Requested**] of Repligen’s written notice to BioMarin that [**Confidential Treatment Requested**], the Parties [**Confidential Treatment Requested**]. As part of any such [**Confidential Treatment Requested**], Repligen shall, [**Confidential Treatment Requested**]. For clarity, BioMarin shall [**Confidential Treatment Requested**] except [**Confidential Treatment Requested**].

7. INDEMNIFICATION.

7.1 Indemnification by Repligen. Repligen shall defend, indemnify, and hold BioMarin and its Affiliates and their respective officers, directors, employees, and agents (the “BioMarin Indemnitees”) harmless from and against any and all damages or other amounts payable to a Third Party claimant, as well as any reasonable attorneys’ fees and costs of litigation incurred by such BioMarin Indemnitees (collectively, “BioMarin Damages”), all to the extent resulting from any claims, suits, proceedings or causes of action brought by such Third Party against such BioMarin Indemnitee (collectively, “BioMarin Claims”) that arise from or are based on: (a) [**Confidential Treatment Requested**]; or (b) [**Confidential Treatment Requested**]. The foregoing indemnity obligation shall not apply to the extent that [**Confidential Treatment Requested**].

7.2 Indemnification by BioMarin. BioMarin shall defend, indemnify, and hold Repligen and its Affiliates and their respective officers, directors, employees, and agents (the “Repligen Indemnitees”) harmless from and against any and all damages or other amounts payable to a Third Party claimant, as well as any reasonable attorneys’ fees and costs of litigation incurred by such BioMarin Indemnitees (collectively, “Repligen Damages”), all to the extent resulting from any claims, suits, proceedings or causes of action brought by such Third Party

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against such Repligen Indemnitee (collectively, “Repligen Claims”) that arise from or are based on: (a) [**Confidential Treatment Requested**], or (b) [**Confidential Treatment Requested**], or (c) [**Confidential Treatment Requested**]. The foregoing indemnity obligation shall not apply to the extent that (i) the Repligen Indemnitees fail to comply with the indemnification procedures set forth in Section 7.3 and [**Confidential Treatment Requested**], or (ii) [**Confidential Treatment Requested**].

7.3 Indemnification Procedures. The Party claiming indemnity under this Article 7 (the “Indemnified Party”) shall give written notice to the Party from whom indemnity is being sought (the “Indemnifying Party”) promptly after learning of such BioMarin Claims or Repligen Claims (as applicable) (each a “Claim”). The Indemnified Party shall provide the Indemnifying Party with reasonable assistance, at the Indemnifying Party’s expense, in connection with the defense of the Claim for which indemnity is being sought. The Indemnified Party may participate in and monitor such defense with counsel of its own choosing at its sole expense; provided, however, the Indemnifying Party shall have the right to assume and conduct the defense of the Claim with counsel of its choice. [**Confidential Treatment Requested**] If the Indemnifying Party does not assume and conduct the defense of the Claim as provided above, (a) the Indemnified Party may defend against, consent to the entry of any judgment, or enter into any settlement with respect to such Claim in any manner the Indemnified Party may deem reasonably appropriate (and the Indemnified Party need not consult with, or obtain any consent from, the Indemnifying Party in connection therewith), and (b) the Indemnifying Party shall remain responsible to indemnify the Indemnified Party as provided in this Article 7.

7.4 Limitation of Liability. NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY SPECIAL, INCIDENTAL, PUNITIVE, OR INDIRECT DAMAGES OR LOSS OF PROFITS ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT, REGARDLESS OF ANY NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. NOTWITHSTANDING THE FOREGOING, NOTHING IN THIS SECTION 6.4 IS INTENDED TO OR SHALL LIMIT OR RESTRICT [**Confidential Treatment Requested**].

7.5 Insurance. Each Party shall procure and maintain insurance adequate to cover its activities hereunder, consistent with normal business practices of prudent companies similarly situated at all times during which any Product is being clinically tested in human subjects or commercially distributed or sold by such Party. It is understood that such insurance shall not be construed to create a limit of either Party’s liability with respect to its indemnification obligations under this Article 7. Each Party shall provide the other Party with written evidence of such insurance upon request.

8. INTELLECTUAL PROPERTY.

8.1 Patent Prosecution.

(a) Scripps Patents. The preparation, filing, prosecution, maintenance and enforcement of the Scripps Patents will be carried out by [**Confidential Treatment Requested**], and Repligen will have no rights or obligations with respect to such preparation, filing, prosecution, and maintenance of the Scripps Patents.

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(b) Repligen Patents. BioMarin shall have the sole right to file, prosecute, and maintain the Repligen Patents and shall use Commercially Reasonable Efforts to do so in order to support the development and commercialization of Products. Repligen shall provide BioMarin all reasonable assistance and cooperation, [**Confidential Treatment Requested**], in BioMarin’s patent prosecution efforts with respect to such Patents, including providing any necessary powers of attorney, executing any other required documents or instruments for such prosecution and making inventors available for consultations, declaration, examiner interviews and the like. [**Confidential Treatment Requested**] In addition, at Repligen’s request, [**Confidential Treatment Requested**] of the Repligen Patents. If BioMarin decides to abandon any of the Repligen Patents Families based on the applications: (i) [**Confidential Treatment Requested**]; (ii) [**Confidential Treatment Requested**]; (iii) [**Confidential Treatment Requested**]; or (iv) [**Confidential Treatment Requested**], as set forth in Exhibit B, BioMarin will notify Repligen at least [**Confidential Treatment Requested**] in advance of the event that would result in abandonment of such Repligen Patent Family, [**Confidential Treatment Requested**] As used in this Section 8.1(b), a Repligen Patent Family means one of the applications listed in the preceding sentence and any Repligen Patent derived from and claiming priority to such application; provided that, with respect to the provisional application, [**Confidential Treatment Requested**] A Repligen Patent Family shall be considered to be abandoned by BioMarin if BioMarin has chosen to terminate patent prosecution of the last Valid Claim of all Repligen Patents within such Repligen Patent Family. [**Confidential Treatment Requested**] [**Confidential Treatment Requested**]

8.2 Infringement of Repligen Patents by Third Parties.

(a) Notification. If Repligen becomes aware of any existing or threatened infringement of any Repligen Patent by a Third Party, (an “Infringement”), it shall promptly notify BioMarin in writing to that effect and the Parties will consult with each other regarding any actions to be taken with respect to such Infringement.

(b) Enforcement Rights. BioMarin shall have the sole right, but not the obligation, to bring an appropriate suit or other action against any person or entity engaged in such Infringement, [**Confidential Treatment Requested**]

(c) Collaboration. Repligen shall provide to BioMarin (i) all Information available to Repligen regarding such alleged Infringement and (ii) reasonable assistance in such enforcement described in subsection (b), [**Confidential Treatment Requested**], including joining such action as a party plaintiff if required by applicable Laws to pursue such action.

(d) Settlement. BioMarin shall have the sole authority, at its sole discretion, to settle any claim, suit or action regarding an Infringment.

(e) Expenses and Recoveries. [**Confidential Treatment Requested**] If BioMarin recovers monetary damages in such claim, suit or action, such recovery shall be allocated first to [**Confidential Treatment Requested**], and any remaining amounts shall be [**Confidential Treatment Requested**].

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(f) Trademarks. BioMarin shall have the right to brand the Products using BioMarin-related trademarks and any other trademarks and trade names it determines appropriate for the Products, which may vary by country or within a country (“Product Marks”); provided that BioMarin shall not, and shall ensure that its Affiliates and licensees will not, make any use of the trademarks or house marks of Repligen (including Repligen’s corporate name) or any trademark confusingly similar thereto. BioMarin shall own all rights in the Product Marks and shall register and maintain, at its own cost and expense, the Product Marks in the countries and regions that it determines reasonably necessary.

9. TREATMENT OF CONFIDENTIAL INFORMATION.

For purposes of this Agreement, “Confidential Information” shall mean all non-public scientific, technical, financial or business information which is disclosed by BioMarin to Repligen, whether in writing, or by oral or visual disclosure or presentation, and which is treated by BioMarin as confidential or proprietary; provided, that all Repligen Technology and the Scripps Patents are also deemed to be Confidential Information of BioMarin. Notwithstanding the foregoing, “Confidential Information” shall not include information that Repligen can demonstrate by competent evidence:

(a) was already known to Repligen, other than under an obligation of confidentiality, at the time of disclosure by BioMarin;

(b) was generally available to the public or otherwise part of the public domain at the time of its disclosure to Repligen;

(c) became generally available to the public or otherwise part of the public domain after its disclosure and other than through any act or omission of Repligen in breach of this Agreement;

(d) is independently discovered or developed by Repligen (outside of the Research) without the use of Confidential Information of BioMarin; or

(e) was disclosed to Repligen, on a non-confidential basis, by a third party who had no obligation to BioMarin not to disclose such information to others.

Notwithstanding the foregoing, Repligen shall not be prohibited from disclosing BioMarin’s Confidential Information to the extent such information is required to be disclosed by court order or by applicable law or government regulation; provided, however, that in such event, Repligen shall give reasonable advance notice (except where impracticable) to BioMarin of such required disclosure and, at BioMarin’s request and expense, shall cooperate with BioMarin’s efforts to contest such disclosure, and/or to obtain a protective order or other confidential treatment of the Confidential Information required to be disclosed.

Repligen agrees that it will hold Confidential Information received from BioMarin in secrecy and confidence and will not disclose it to any Third Party, or use it for any purpose, other than for the purpose of the performance of this Agreement. Repligen further agrees that it will restrict disclosure of Confidential Information within its own organization and Affiliates to those persons having a need to know it for the purpose of this Agreement, and that such persons will

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be advised of the obligation set forth in this Agreement and obligated in like fashion. If Repligen learns of any disclosure by it or its employees, agents, independent contractors, or Affiliates of any Confidential Information of BioMarin not in accordance with this Section 9, Repligen shall promptly notify BioMarin of such unauthorized disclosure.

The above obligations of Repligen with respect to its treatment of Confidential Information shall commence as of the Effective Date and continue for a period of ten (10) years following disclosure of such Confidential Information. This Agreement shall not be construed as granting any license rights with respect to the Confidential Information. Except as otherwise required by applicable laws and regulations or rules of any securities exchange, the Parties hereby agree that any disclosure of the terms and conditions of this Agreement shall be subject to the other Party’s prior written agreement; provided, however, that each Party may disclose the terms and conditions of this Agreement to a prospective or actual investor, acquirer, licensee or collaborator pursuant to a written confidentiality agreement of the same or more restrictive provisions as those contained herein, and provided further that if any such disclosure is required by laws, regulations or rules of a securities exchange, the Party required to make such disclosure shall notify the other Party of any such disclosure and shall seek confidential treatment of portions of this Agreement where reasonably available.

10. NOTICES.

10.1 All notices and statements to either Party required under this Agreement shall be made in writing delivered via certified mail, return receipt requested, courier, provided that evidence of delivery is made, or facsimile with confirmation of such transmission addressed to such Party at the following addresses or faxed to the appropriate numbers set forth below (with the copies to other Parties set forth below) or to such other address as may be designated from time to time:

To Repligen:

Repligen Corporation

41 Seyon Street

Building 1, Suite 100

Waltham, MA 02453

Attn: President Fax: (781)250-0115

To BioMarin:

BioMarin Pharmaceutical Inc.

105 Digital Drive

Novato, CA 94949

Attn: General Counsel

Fax: (415) 382-7889

10.2 All notices and statements provided to a Party hereunder shall be deemed to have been given as of the date received, or at the time of delivery of a facsimile to the relevant facsimile number above.

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10.3 Each Party hereto may change its address and contact information set forth above for the purpose of this Agreement by providing written notice to the other Party of the same from time to time.

11. DISPUTE RESOLUTION

11.1 Executive Officers. Unless otherwise set forth in this Agreement, in the event of a dispute arising under this Agreement between the Parties, the Parties shall refer such dispute to the respective Executive Officers, and such Executive Officers shall attempt in good faith to resolve such dispute. Either Party may initiate such informal dispute resolution by sending written notice of the dispute to the other Party, and, within twenty (20) days after such notice, such Executive Officers shall meet for attempted resolution by good faith negotiations. If such Executive Officers are unable to resolve such dispute within thirty (30) days of their first meeting for such negotiations, either Party may seek to have such dispute resolved in accordance with the following Sections 11.2 and 11.3.

11.2 Governing Law. This Agreement shall be governed and interpreted in accordance with the laws of the State of California, without regard to conflict of law provisions.

11.3 Jurisdiction; Venue. Any dispute arising under this Agreement, or other legal proceeding relating to this Agreement or the enforcement of any provision of this Agreement must be brought or otherwise commenced solely and exclusively in courts of competent jurisdiction located in the city of San Francisco, California. Consistent with the preceding sentence, each of the Parties: (a) expressly and irrevocably consents and submits to the jurisdiction of the courts of competent jurisdiction in the city of San Francisco, California (and each appellate court located in the State of California) in connection with any such legal proceeding; (b) expressly agrees that the courts of competent jurisdiction in the city of San Francisco, California shall be deemed to be a convenient forum; and (c) expressly agrees not to assert (by way of motion, as a defense or otherwise), in any such legal proceeding commenced in the courts of competent jurisdiction in the city of San Francisco, California, any claim that such Party is not subject personally to the jurisdiction of such court, that such legal proceeding has been brought in an inconvenient forum, that the venue of such proceeding is improper or that this Agreement or the subject matter of this Agreement may not be enforced in or by such court.

12. MISCELLANEOUS.

12.1 Acknowledgement. Each Party acknowledges that it has negotiated and entered into this Agreement in good faith.

12.2 Severability. If any provision of this Agreement is held by a court of competent jurisdiction to be invalid or unenforceable, it shall be modified, if possible, to the minimum extent necessary to make it valid and enforceable or, if such modification is not possible, it shall be stricken and the remaining provisions shall remain in full force and effect.

12.3 Interpretation.

(a) The English language of this Agreement shall govern any interpretation of or dispute regarding this Agreement.

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(b) Any reference in this Agreement to a Section or Exhibit is a reference to the Sections and Exhibits of this Agreement unless the context requires otherwise. Any reference to a Section shall be deemed to include a reference to any subsidiary Sections.

(c) The captions of the Sections are included for reference purposes only and are not intended to be a part of the Agreement or in any way to define, limit or describe the scope or intent of the particular provision to which they refer.

(d) Whenever the context requires: the singular number shall include the plural and vice versa; the masculine gender shall include the feminine and neuter gender; the feminine gender shall include the masculine and neuter gender; and the neuter gender shall include the feminine and masculine gender.

(e) The Parties agree that any rule of construction to the effect that ambiguities are to be resolved against the drafting party shall not be applied in the construction or interpretation of this Agreement.

(f) As used in this agreement “include” and “including” and variations thereof shall not be deemed to be terms of limitation, but rather shall be deemed to be followed by the words “without limitation.”

12.4 Assignment. This Agreement shall not be assigned by either Party, without the prior written consent of the other Party; provided that BioMarin may assign this Agreement without such consent: (i) to an Affiliate of BioMarin; (ii) in the event of a merger, consolidation or similar reorganization of BioMarin with or into a Third Party, whether by acquisition, merger, sale of stock, change of control or otherwise, or (iii) in the event of a sale of all or substantially all of the assets of BioMarin to which this Agreement relates, this Agreement shall be assigned to or become the obligation and liability of the acquiring entity. Any purported assignment in violation of this Section 12.4 shall be void.

12.5 Force Majeure. If the performance of this Agreement or any obligation hereunder (except for the payment of money) is prevented, restricted or interfered with by reason of fire or other casualty or accident, strikes or labor disputes, inability to procure raw materials, power or supplies, war, invasion, civil commotion or other violence, compliance with any order of any governmental authorities or any other act or conditions whatsoever beyond the reasonable control of either Party hereto, the Party so affected upon giving a prompt notice to the other Party shall be excused from such performance to the extent of such prevention, restriction or interference; provided, however, that the Party so affected shall use commercially reasonable efforts to avoid or remove such causes of non-performance and shall continue performance hereunder with the utmost dispatch whenever such causes are removed, to the extent commercially reasonable.

12.6 Entirety of Agreement. This Agreement contains the entire understanding of the Parties hereto with respect to the subject matter contained herein. There are no restrictions, promises, covenants or understandings other than those expressly set forth herein, and no rights or duties on the part of either Party are to be implied or inferred beyond those expressly herein provided for. The Parties may, from time to time during the term of this Agreement, amend, modify, vary, waive or alter any of the provisions of this Agreement, but only by a written instrument that makes specific reference to this Agreement which is duly executed by each Party, or in the case of waiver, by the Party or Parties waiving compliance.

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12.7 Further Assurances. Each Party agrees to duly execute and deliver, or cause to be duly executed and delivered, such further instruments and do and cause to be done such further acts and things, including, without limitation, the filing of such additional assignments, agreements, documents and instruments, that may be necessary or as the other Party hereto may at any time and from time to time reasonably request in connection with this Agreement or to carry out more effectively the provisions and purposes of, or to better assure and confirm unto such other Party its rights and remedies under, this Agreement.

12.8 No Partnership. For the purposes of this Agreement and all obligations to be performed hereunder, each Party shall be, and shall be deemed to be, an independent contractor and not an agent, partner, joint venturer or employee of the other Party. Neither Party shall have authority to make any statements, representations or commitments of any kind, or to take any action which shall be binding on the other Party, except as may be explicitly provided for herein or authorized in writing.

12.9 Use of Other Party’s Name. Neither Party shall use the name, trademark, trade name or logo of the other Party or their respective employee(s) in any publicity, promotion, press release or disclosure relating to this Agreement or its subject matter, without the prior express written permission of the other Party, except as may be required by applicable laws or regulations.

12.10 Waiver. The waiver by either Party of any breach, default or omission in the performance or observance of any of the terms of this Agreement by the other Party shall not be deemed to be a waiver of any other such breach, default or omission. Any waiver of this Agreement must be in writing and signed by the waiving Party to be effective.

12.11 Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed an original, and all of such counterparts taken together shall constitute one and the same instrument. Counterparts may be signed and delivered by facsimile, each of which shall be binding when sent.

[SIGNATURE PAGE FOLLOWS]

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IN WITNESS WHEREOF, the parties hereto, intending to be legally bound hereby, have duly executed this Asset Purchase and Research Agreement to be effective as of the Effective Date.

BIOMARIN PHARMACEUTICAL INC.		REPLIGEN CORPORATION
By:	/s/ Scott Clarke	By:	/s/ Howard Benjamin
Name: Scott Clarke		Name:	Howard Benjamin
Title: VP BD & Scientific Licensing		Title:	VP BD

EXHIBIT A

Repligen Library Compound

Comp_ID RGFP#	Structure
[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EXHIBIT B

Repligen Patents

WO (Family) Number	F&R #	STATUS	APPLN #	FILED	PATENT #	ISSUED	TITLE
[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EXHIBIT C

Scripps Agreement

[Omitted]

Already filed as Exhibit 10.18 to Repligen Corporation’s Annual Report on Form 10-K for the year ended March 31, 2007 and incorporated herein by reference.

EXHIBIT D

Biological Materials and Reagents to be Transferred to BioMarin

Summary of chemical and biological material Repligen will transfer to BioMarin upon signing of the agreement:

1. [**Confidential Treatment Requested**]

2. [**Confidential Treatment Requested**]

3. [**Confidential Treatment Requested**]

4. [**Confidential Treatment Requested**]

[**Confidential Treatment Requested**]

Note: all quantities are approximation

X g compound available in bigger bottles in indicated quantity compound is no longer available compound available in small vials

Comp_ID RGFP #	Structure	< 10 mg vials	large bottles	not available
[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EXHIBIT E

Reimbursable Activities

[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EXHIBIT F

Foundation Grants

Agency	Execution Date	Goal	Amount
[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EXHIBIT G

Owned Repligen Technology

[**Confidential Treatment Requested**]

CERTAIN CONFIDENTIAL PORTIONS OF THIS EXHIBIT WERE OMITTED AND REPLACED WITH “[**Confidential Treatment Requested**]”. A COMPLETE VERSION OF THIS EXHIBIT HAS BEEN FILED SEPARATELY WITH THE SECRETARY OF THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO AN APPLICATION REQUESTING CONFIDENTIAL TREATMENT UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934.

EX-10.3

Exhibit 10.3

FOURTH AMENDMENT

THIS FOURTH AMENDMENT TO LEASE (the “Amendment”) is made and entered into as of the date of final execution (“Effective Date”), by and between CENTERPOINT ACQUISITIONS LLC, a Delaware limited liability company (“Landlord”), and REPLIGEN CORPORATION, a Delaware corporation (“Tenant”).

RECITALS

A. Landlord and Tenant are parties to that certain lease dated October 10, 2001, as amended by a Letter Agreement dated May 7, 2002, a First Amendment dated June 29, 2011 (“First Amendment”), a Second Amendment dated as of January 11, 2013, and a Third Amendment dated September 26, 2013, (collectively, the “Lease”). Pursuant to the Lease, Landlord has leased to Tenant space currently containing 55,694 rentable square feet (the “Original Premises”) on the 1^st floor of the building commonly known as 41 Seyon Street located at 41 Seyon Street, Waltham, Massachusetts (the “Building”) for a Term that is scheduled to expire on May 31, 2023.

B. Tenant has, by letter dated February 26, 2014, exercised its Right of First Refusal, pursuant to Section VIII of the First Amendment, to lease additional space containing approximately 19,900 rentable square feet on the 1^st and 2^nd floor of the Building shown on Exhibit A, Fourth Amendment, attached hereto (the “Expansion Space”). Landlord is willing to do the same on the following terms and conditions.

NOW, THEREFORE, in consideration of the mutual covenants and agreements herein contained and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Landlord and Tenant agree as follows:

I. Expansion and Effective Date.

Effective as of the Expansion Effective Date (defined below), the Premises, as defined in the Lease, is increased from 55,694 rentable square feet on the 1^st floor to 75,594 rentable square feet on the 1^st and 2^nd floors by the addition of the Expansion Space, and from and after the Expansion Effective Date, the Original Premises and the Expansion Space, collectively, shall be deemed the Premises, as defined in the Lease. The Term for the Expansion Space shall commence on the Expansion Effective Date and end on the date that is eight (8) years and one (1) month after the Expansion Effective Date (“Expansion Termination Date”). The Expansion Space is subject to all the terms and conditions of the Lease except as expressly modified herein and except that Tenant shall not be entitled to receive any allowances, abatements or other financial concessions granted with respect to the Original Premises unless such concessions are expressly provided for herein with respect to the Expansion Space.

A. The Expansion Effective Date shall be the later to occur of (i) August 1, 2014 (“Target Expansion Effective Date”) and (ii) the date upon which the Landlord Work (as defined in the Work Letter attached as Exhibit B hereto) in the Expansion Space has been substantially completed; provided, however, that if Landlord shall be delayed in substantially completing the Landlord Work in the Expansion Space as a result of the occurrence of a Tenant Delay (defined below), then, for purposes of determining the Expansion Effective Date, the date of substantial completion shall be deemed to be the day that said Landlord Work

would have been substantially completed absent any such Tenant Delay(s). A “Tenant Delay” means any act or omission of Tenant or its agents, employees, vendors or contractors that actually delays substantial completion of the Landlord Work, including, without limitation, the following:

1. Tenant’s failure promptly to furnish information or approvals after Landlord’s reasonable request therefor, including the failure to prepare or approve preliminary or final plans by any applicable due date as otherwise provided, if at all, in this Amendment or the exhibits hereto;

2. Tenant’s selection of equipment or materials that have long lead times after first being informed by Landlord that the selection may result in a delay;

3. Changes made by Tenant to the plans and specifications attached hereto as Exhibit B-1 and approved by Landlord, provided that Landlord has delivered to Tenant an estimate of the additional time period to effect such changes and Tenant has approved such additional period of time;

4. The performance of work in the Expansion Space by Tenant or Tenant’s contractor(s) during the performance of the Landlord Work; or

5. If the performance of any portion of the Landlord Work depends on the prior or simultaneous performance of work by Tenant, a delay by Tenant or Tenant’s contractor(s) in the completion of such work.

The Expansion Space shall be deemed to be substantially completed on the date that all Landlord Work has been performed (or would have been performed absent any Tenant Delays), other than any minor details of construction, mechanical adjustment or any other matter, the noncompletion of which does not unreasonably interfere with Tenant’s use of the Expansion Space and can be completed within thirty (30) days after the date of substantial completion. The parties agree to meet within three (3) Business Days after Landlord’s notice of Substantial Completion to review the Expansion Space and agree upon the remaining punch list items to be completed. The adjustment of the Expansion Effective Date and, accordingly, the postponement of Tenant’s obligation to pay Rent on the Expansion Space shall be Tenant’s sole remedy and shall constitute full settlement of all claims that Tenant might otherwise have against Landlord by reason of the Expansion Space not being ready for occupancy by Tenant on the Target Expansion Effective Date.

B. In addition to the postponement, if any, of the Expansion Effective Date as a result of the applicability of Paragraph I.A. of this Amendment, the Expansion Effective Date shall be delayed to the extent that Landlord fails to deliver possession of the Expansion Space for any other reason (other than Tenant Delays by Tenant), including but not limited to, holding over by prior occupants. Any such delay in the Expansion Effective Date shall not subject Landlord to any liability for any loss or damage resulting therefrom. If the Expansion Effective Date is delayed, the Termination Date under the Lease shall not be similarly extended.

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II. Basic Rent.

Initial Rate. In addition- to Tenant’s obligation to pay Basic Rent for the Original Premises, Tenant shall pay Basic Rent for the Expansion Space as follows:

Lease Year*	Annual Rate Per Square Foot (subject to adjustment as provided below)		Annual Base Rent			Monthly Base Rent
Lease Year 1	$	18.00	$	270,000.00	**	$	22,500.00
Lease Year 2	$	18.00	$	306,000.00	***	$	25,500.00
Lease Year 3-5	$	19.00	$	378,100.00	****	$	31,508.33
Lease Year 6-8	$	20.00	$	398,000.00	****	$	33,166.67

* For purposes hereof, an “Lease Year” shall mean a 12 month period beginning on the Expansion Effective Date, or any anniversary of the Expansion Effective Date, except that if the Expansion Effective Date does not fall on the first day of a calendar month, then the first Lease Year shall begin on the Expansion Effective Date, and end on the last day of the month containing the first anniversary of the Expansion Effective Date (and the Basic Rent for such first Lease Year shall be prorated to reflect the additional days included therein), and each succeeding Lease Year shall begin on the day following the last day of the prior Lease Year.

** Based on 15,000 square feet

*** Based on 17,000 square feet

**** Based on 19,900 square feet

All such Basic Rent and Additional Rent payable on account of Taxes, Operating Expenses, and utilities shall be payable by Tenant in accordance with the terms of the Lease.

Tenant shall have no obligation to pay Basic Rent for the first (1^st) full calendar month of Lease Year 1.

III. Additional Security Deposit/Letter of Credit.

Upon Tenant’s execution hereof, Tenant shall deliver to Landlord an additional Security Deposit in the amount of $250,000.00 which is added to and becomes part of the Security Deposit, if any, held by Landlord as provided under Section 14.8 of the Lease as security for payment of Rent and the performance of the other terms and conditions of the Lease by Tenant. Accordingly, simultaneously with the execution hereof, the Letter of Credit shall be increased from $250,000.00 to $450,000.00. Tenant shall provide the additional Security Deposit by delivery to Landlord of an additional Letter of Credit in the amount of the increase (i.e., $250,000.00), or an amendment to the Letter of Credit increasing it to the increased amount (i.e., $450,000.00) or a substitute Letter of Credit in the increased amount, whereupon Landlord shall return the original Letter of Credit. The provisions of Section 14.8(c) no longer apply to the Security Deposit and are hereby deleted from the Lease.

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IV. Tenant’s Proportionate Share.

For the period commencing with the Expansion Effective Date and ending on the Expansion Termination Date, Tenant’s Proportionate Share for the entire Premises, including the Original Premises and Expansion Space shall be 15.12%.

V. Intentionally Omitted.

VI. Improvements to Expansion Space.

A. Condition of Expansion Space. Tenant has inspected the Expansion Space and agrees to accept the same “as is” without any agreements, representations, understandings or obligations on the part of Landlord to perform any alterations, repairs or improvements, except as may be expressly provided otherwise in this Amendment.

B. Responsibility for Improvements to Expansion Space. Landlord shall perform improvements to the Expansion Space in accordance with the Work Letter attached hereto as Exhibit B.

VII. Early Access to Expansion Space.

During any period that Tenant shall be permitted to enter the Expansion Space prior to the Expansion Effective Date, Tenant shall comply with all terms and provisions of the Lease, except those provisions requiring payment of Basic Rent or Additional Rent as to the Expansion Space. If Tenant takes possession of the Expansion Space prior to the Expansion Effective Date for any reason whatsoever (other than the performance of work in the Expansion Space with Landlord’s prior approval), such possession shall be subject to all the terms and conditions of the Lease and this Amendment, and Tenant shall pay Basic Rent and Additional Rent as applicable to the Expansion Space to Landlord on a per diem basis for each day of occupancy prior to the Expansion Effective Date.

VIII. Electricity with Respect to Expansion Space. Landlord shall, as part of Landlord’s Work, install a submeter in the Expansion Space to measure the consumption of electricity in the Expansion Space and Tenant shall reimburse Landlord for the cost of such electric current (at the same rate per kilowatt hour paid by Landlord to the utility provider from time to time) as measured by the submeter within thirty (30) days after delivery of Landlord’s invoice therefor.

IX. Roof Terrace. Tenant shall have the right, at Tenant’s sole cost and expense, to construct a roof terrace on the roof of the Building (“Roof Terrace”), provided that (a) no Default of Tenant has occurred and remains uncured hereunder, (b) Landlord approves in writing the location, size and appearance of the Roof Terrace, which approval may be withheld or conditioned at Landlord’s sole discretion, (c) the Roof Terrace is in compliance with all applicable laws, codes and ordinances and Tenant has obtained all governmental permits and approvals required in connection therewith, (d) the installation, maintenance and removal of the Roof Terrace (including, without limitation, the repair and cleaning of the

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roof of the Building upon removal of the Roof Terrace) is performed at Tenant’s expense in accordance with the terms and conditions governing alterations pursuant to Section 5.2 of the Lease and Landlord’s reasonable regulations. If Landlord has approved same, Landlord agrees to cooperate with Tenant for the construction and permitting of the Roof Terrace.

Landlord shall have the right to prescribe reasonable rules and regulations for Tenant’s use of the Roof Terrace from time to time. Such rules shall in any event include, without limitation, that no cooking of any sort shall be permitted on the Roof Terrace, that no one shall lean over the edge of the Roof Terrace at any time, that nothing shall be hung on or displayed from the Roof Terrace railings, that no one shall throw, sweep, shovel or otherwise dispose of anything over the edge of the Roof Terrace, and that all items placed in the Roof Terrace shall be secured such that the same cannot be blown off the Roof Terrace by high winds. If Landlord notifies Tenant in writing that a violation of the Roof Terrace rules and regulations has occurred, and thereafter the same or a similar violation occurs beyond applicable notice and cure periods, Landlord shall have the right to revoke Tenant’s right to use the Roof Terrace. If Tenant constructs the Roof Terrace, Tenant shall, at Tenant’s cost and expense, be responsible for (i) cleaning, repairing and maintaining the Roof Terrace throughout the Term of the Lease and (ii) for performing any maintenance, repairs, or replacement to the Building made necessary or advisable by reason of the presence thereon of the Roof Terrace or the installation of same.

X. Signage. Landlord shall, at Landlord’s cost and expense, install standard Building signage at the entrance to the Expansion Space. The initial listing of Tenant’s name shall be at Landlord’s cost and expense. Any changes, replacements or additions by Tenant to such directory shall be at Tenant’s sole cost and expense.

Tenant shall have the right to replace the existing Tenant sign on the north façade of the Building with a larger sign in accordance with plans and specifications therefor approved in advance, in writing by Landlord, which approval shall not be unreasonably withheld, subject in any event to the terms and conditions of Section 5.1 (b)(ii) of the Lease.

XI. Options to Extend. Tenant’s right and option to extend the Term of the Lease pursuant to Section 2.4 of the Lease, as amended by Section IX of the First Amendment, shall apply to the Expansion Space, except that the Basic Rent for the Extension Term with respect to the Expansion Space shall be equal to 100% of the Fair Market Rental Value of the Expansion Space. The parties acknowledge that the Expansion Termination Date does not coincide with the Extended Termination Date (as that term is defined in the First Amendment) and, therefore, agree that the time period for the exercise of the option and the periods of the extended Terms will differ with respect to the Original Premises and the Expansion Space.

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XII. Right of First Offer.

A. Grant of Option; Conditions. Tenant shall have the one time right of first offer (the “Right of First Offer”) with respect to any available space in the Building. Tenant’s Right of First Offer shall be exercised as follows: at any time after Landlord has determined that available space (the “Offering Space”) exists, then, before leasing such Offering Space to a party other than the existing tenant thereof or any party holding existing rights in such Offering Space as of the date of this Amendment. Landlord shall give Tenant written notice (the “Advice”) of the terms under which Landlord is prepared to lease the Offering Space to Tenant. Tenant may lease such Offering Space in its entirety only, under such terms, by delivering written notice of exercise to Landlord (the “Notice of Exercise”) within 5 Business Days after the date of the Advice, except that Tenant shall have no such Right of First Offer and Landlord need not provide Tenant with an Advice, if:

(i) Tenant is in default under the Lease beyond any applicable cure periods at the time that Landlord would otherwise deliver the Advice; or

(ii) the Premises, or any portion thereof, is sublet at the time Landlord would otherwise deliver the Advice (except pursuant to Section 6.1(b)); or

(iii) the Lease has been assigned prior to the date Landlord would otherwise deliver the Advice (except pursuant to Section 6.1(b)); or

(iv) Tenant is not occupying the Premises on the date Landlord would otherwise deliver the Advice; or

(v) the Offering Space is not intended for the exclusive use of Tenant during the Term; or

(vi) the existing tenant in the Offering Space is interested in extending or renewing its lease for the Offering Space or entering into a new lease for such Offering Space; or

(vii) Tenant has previously leased Offering Space pursuant to this Right of First Offer; or

(viii) Landlord has previously delivered an Advice to Tenant and Tenant has not timely delivered a Notice of Exercise with respect thereto (subject, however, to the provisions of Section C below).

B. Terms for Offering Space.

(ix) The term for the Offering Space shall commence upon the commencement date stated in the Advice and thereupon such Offering Space shall be considered a part of the Premises, provided that all of the terms stated in the Advice shall govern Tenant’s leasing of the Offering Space and only to the extent that they do not conflict with the Advice, the terms and conditions of this Lease shall apply to the Offering Space.

(x) Tenant shall pay Basic Rent and Additional Rent for the Offering Space in accordance with the terms and conditions of the Advice.

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(xi) The Offering Space (including improvements and personalty, if any) shall be accepted by Tenant in its condition and as-built configuration existing on the earlier of the date Tenant takes possession of the Offering Space or as of the date the term for such Offering Space commences, unless the Advice specifies any work to be performed by Landlord in the Offering Space, in which case Landlord shall perform such work in the Offering Space. If Landlord is delayed delivering possession of the Offering Space due to the holdover or unlawful possession of such space by any party, Landlord shall use reasonable efforts to obtain possession of the space, and the commencement of the term for the Offering Space shall be postponed until the date Landlord delivers possession of the Offering Space to Tenant free from occupancy by any party.

C. Termination of Right of First Offer. The rights of Tenant hereunder with respect to the Offering Space shall terminate on the earliest to occur of: (i) Tenant’s failure to exercise its Right of First Offer within the 5 Business Day period provided in Section A above; (iii) the date Landlord would have provided Tenant an Advice if Tenant had not been in violation of one or more of the conditions set forth in Section A above, and (iii) the date that Tenant exercises its Right of First Offer with respect to any portion of the Offering Space. Notwithstanding the foregoing, in the event that the Right of First Offer terminates pursuant to clause (i) above, Landlord shall not lease the Offering Space to another party (other than the current occupant thereof) at a Net Effective Rent (defined below) less than ninety percent (90%) of the Net Effective Rent set forth in the Advice without first giving Tenant another Advice at such lower Net Effective Rent. The term “Net Effective Rent” shall mean the net present value as reasonably determined by Landlord of the aggregate consideration, determined on an average annual basis, payable to Landlord under the proposal at issue (i.e., either the Advice or the offer to another party, as the case may be), taking into account all base rent, additional rent, free rent, construction or other allowances, the cost of any work performed in the Offering Space by Landlord at its expense, the length of lease term, and all other relevant economic terms.

D. Offering Amendment. If Tenant exercises its Right of First Offer, Landlord shall prepare an amendment (the “Offering Amendment”) adding the Offering Space to the Premises on the terms set forth in the Advice and reflecting the changes in the Base Rent, Rentable Square Footage of the Premises, Tenant’s Pro Rata Share and other appropriate terms. A copy of the Offering Amendment shall be sent to Tenant within a reasonable time after Landlord’s receipt of the Notice of Exercise executed by Tenant, and Tenant shall execute and return the Offering Amendment to Landlord within 15 days thereafter, but an otherwise valid exercise of the Right of First Offer shall be fully effective whether or not the Offering Amendment is executed.

E. Subordination. Notwithstanding anything herein to the contrary, Tenant’s Right of First Offer is subject and subordinate to the expansion rights (whether such rights are designated as a right of first offer, right of first refusal, expansion option or otherwise) of any tenant of the Building existing on the date hereof, which rights are identified on Exhibit D.

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XIII. Parking. In addition to Tenant’s parking rights pursuant to Section 2.3 of the Lease, as amended by Section XI of the First Amendment, Tenant shall have the right to use, on a non-exclusive, unreserved basis, 69 parking spaces in the Parking Area. In addition to such unreserved spaces, Tenant shall have the right to use, on a reserved basis, 5 parking spaces near the North entrance to the Building in the location as shown on Exhibit C, Fourth Amendment, attached hereto. Landlord reserves the right, in connection with any future reconfiguration of the Parking Area, to relocate such reserved spaces to a comparable location in the reconfigured Parking Area.

XIV. Interior Stairs. Tenant shall have the right, at Tenant’s sole cost and expense, to interior connecting stairs between the portions of the Premises on the first and second floors (“Stairwell”), provided that (a) the Stairwell is in compliance with all applicable laws, codes and ordinances and Tenant has obtained all governmental permits and approvals required in connection therewith, (b) the installation, maintenance and removal of the Stairwell is performed at Tenant’s expense in accordance with plans and specifications therefor that had been approved in writing, in advance by Landlord, which approval shall not be unreasonably withheld and the terms and conditions governing alterations pursuant to Section 5.2 of the Lease and Landlord’s reasonable regulations, and (c) Tenant has deposited with Landlord, as an additional Security Deposit, an amount reasonably estimated by Landlord to equal the cost of removing the Stairwell and restoring the affected area of the Premises to its condition immediately preceding the installation of the Stairwell. If Landlord has approved same, Landlord agrees to cooperate with Tenant for the construction and permitting of the Stairwell. Unless Landlord otherwise elects by written notice given at least 120 days prior to the expiration date of the Term for the Expansion Space, Tenant shall remove the Stairwell and restore the floor slab opening in compliance with applicable codes.

XV. Notices. For all purposes of the Lease, the notice address for Landlord is as follows:

Saracen Properties LLC

41 Seyon Street

Suite 200

Waltham, MA 02453

XVI. Inapplicable, Deleted and Confirmed Lease Provisions.

A. Article 4 of the Lease (Commencement and Condition), Exhibit G to the Lease (Base Building Work), Exhibit B to the First Amendment (Work Letter) and Exhibit C to the First Amendment (Refusal Space) shall have no applicability with respect to this Amendment.

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B. Whereas, Tenant exercised its Right of First Refusal pursuant to Section VIII of the First Amendment and Exhibit C to the First Amendment (Refusal Space), Section VIII of the First Amendment and Exhibit C to the First Amendment are hereby deleted and are of no further force or effect.

XVII. Landlord agrees to obtain from the holder of the existing mortgage on the Property a subordination, non-disturbance, and attornment agreement substantially in the form attached hereto as Exhibit E.

XVIII. Miscellaneous.

A. This Amendment sets forth the entire agreement between the parties with respect to the matters set forth herein. There have been no additional oral or written representations or agreements. Under no circumstances shall Tenant be entitled to any Rent abatement, improvement allowance, leasehold improvements, or other work to the Premises, or any similar economic incentives that may have been provided Tenant in connection with entering into the Lease, unless specifically set forth in this Amendment.

B. Except as herein modified or amended, the provisions, conditions and terms of the Lease shall remain unchanged and in full force and effect.

C. In the case of any inconsistency between the provisions of the Lease and this Amendment, the provisions of this Amendment shall govern and control.

D. Submission of this Amendment by Landlord is not an offer to enter into this Amendment but rather is a solicitation for such an offer by Tenant. Neither party shall be bound by this Amendment until both parties have executed and delivered the same to the other party.

E. The capitalized terms used in this Amendment shall have the same definitions as set forth in the Lease to the extent that such capitalized terms are defined therein and not redefined in this Amendment.

F. Tenant hereby represents to Landlord that Tenant has dealt with no broker in connection with this Amendment. Tenant agrees to indemnify and hold Landlord, its trustees, members, principals, beneficiaries, partners, officers, directors, employees, mortgagee(s) and agents, and the respective principals and members of any such agents (collectively, the “Landlord Related Parties”) harmless from all claims of any broker claiming to have represented Tenant in connection with this Amendment. Landlord hereby represents to Tenant that Landlord has dealt with no broker in connection with this Amendment. Landlord agrees to indemnify and hold Tenant, its trustees, members, principals, beneficiaries, partners, officers, directors, employees, and agents, and the respective principals and members of any such agents (collectively, the “Tenant Related Parties”) harmless from all claims of any brokers claiming to have represented Landlord in connection with this Amendment.

G. Each signatory of this Amendment represents hereby that he or she has the authority to execute and deliver the same on behalf of the party hereto for which such signatory is acting.

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[SIGNATURES ARE ON FOLLOWING PAGE]

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IN WITNESS WHEREOF, Landlord and Tenant have duly executed this Amendment as of the day and year first above written.

[Signature Page Fourth Amendment]

EXHIBIT A

OUTLINE AND LOCATION OF EXPANSION SPACE

Exhibit A, Fourth Amendment

EXHIBIT B

WORK LETTER

This Exhibit is attached to and made a part of the Amendment by and between CENTERPOINT ACQUISITIONS LLC, a Delaware limited liability company (successor in interest to TC Saracen, LLC) (“Landlord”), and REPLIGEN CORPORATION, a Delaware corporation (“Tenant”) for space in the Building located at 41 Seyon Street, Waltham, Massachusetts.

As used in this Workletter, the “Premises” shall be deemed to mean the Expansion Space as defined in the attached Amendment.

A. Landlord has previously presented to Tenant the plan prepared by LaFreniere Architects, dated February 13, 2014, attached hereto as Exhibit B-1 (the “Initial Plan”). Tenant shall deliver to Landlord as soon as reasonably possible after the Effective Date any comments and revisions Tenant would like to the Initial Plan and the parties shall review and discuss such comments and revisions in good faith in order to agree upon a mutually acceptable plan for the initial improvements in the Expansion Space. Tenant’s proposed revisions shall use Building Standard methods, materials and finishes and be at least comparable in utility for general office space as provided in the Initial Plan. Within fifteen (15) Business Days after the Effective Date the parties shall agree upon plans and specifications incorporating Tenant’s revisions that were mutually acceptable to the parties and otherwise consistent with Initial Plan (the “Plans”). In the event that the parties are unable to agree in good faith on all or any particular changes or revisions, the Initial Plan shall control and shall constitute the “Plans” for all purposes. The improvements to be performed by Landlord in accordance with the Plans, as further developed and refined into the Construction Drawings (as defined below) are hereinafter referred to as the “Landlord Work.” It is agreed that construction of the Landlord Work is intended to be “turn-key” and will be completed at Landlord’s sole cost and expense in accordance with the Construction Drawings using Building Standard methods, materials and finishes. Landlord shall enter into a direct contract for the Landlord Work with a general contractor selected by Landlord. In addition, Landlord shall have the right to select and/or approve of any subcontractors used in connection with the Landlord Work. Landlord’s Work shall be performed in accordance with the approved Construction Drawings and in compliance with all applicable laws. Landlord’s supervision or performance of any work for or on behalf of Tenant shall not be deemed a representation by Landlord that the improvements constructed in accordance with the Plans and any revisions thereto will be adequate for Tenant’s use.

B. Landlord shall cause the Plans to be developed into construction level plans and specifications for Landlord Work (the “Construction Drawings”) and shall deliver the iterations of the Construction Drawings to Tenant for Tenant’s review and approval, which approval shall not be unreasonably withheld, conditioned or delayed so long as the subject Construction Drawings are consistent with the Plans and prior iterations of the Construction Drawings, and Landlord may disregard any disapproval that is not based on the fact that the subject Construction Drawings are inconsistent with the Plans and prior iterations of the Construction Drawings or do not comply with law (excluding Tenant Change Orders (as defined below) approved by Landlord). If Tenant fails to respond to the Construction Drawings within three (3) Business Days after delivery of same to Tenant, Tenant shall be deemed to have approved the same. If Tenant shall request any revisions to the Plans or Construction Drawings, Landlord shall have such revisions

Exhibit B, Fourth Amendment

prepared and, unless such requested revisions are for purposes of compliance with applicable laws or to conform to the Plans or prior iterations of the Construction Drawings, Tenant shall reimburse Landlord for the cost of preparing any such revisions to the Plans or Construction Drawings, within thirty (30) days after receipt of an invoice. If Tenant shall request any revisions that are not consistent with the Plans or Construction Drawings (“Tenant Change Orders”), promptly upon completion of the revisions, Landlord shall notify Tenant in writing of the estimated impact to the Target Expansion Effective Date and the modifications to the costs of Landlord Work, if any, resulting from such Tenant Change Orders. Tenant, within three (3) Business Days, shall notify Landlord in writing whether it desires to proceed with such Tenant Change Orders. In the absence of such written authorization, Landlord shall have the option to continue work on the Premises disregarding the requested Tenant Change Orders. Tenant shall be responsible for any Tenant Delay in completion of the Premises resulting from such Tenant requested Tenant Change Orders, which Tenant Delay shall include, without limitation, the time period reasonably required for Landlord to prepare any required revisions to the Construction Drawings and the period that elapses after Landlord delivers such revised Construction Drawings until Tenant approves or disapproves same. If such Tenant Change Orders result in an increase in the cost of Landlord Work, such increased costs, plus any applicable state sales or use tax thereon, shall be payable by Tenant within thirty (30) days after receipt of an invoice. Notwithstanding anything herein to the contrary, all revisions to the Plans shall be subject to the approval of Landlord, which approval shall not be unreasonably withheld, conditioned or delayed, provided that the Landlord Work as so modified is, in Landlord’s sole but reasonable discretion, generically reusable for office uses after the termination of the Lease, unless Tenant removes such non-generically reusable improvements and restores the affected area of the Premises to the condition indicated by Exhibit B-1 prior to the expiration of the Term of the Lease and deposits with Landlord, as an additional Security Deposit, an amount reasonably estimated by Landlord to equal the cost of removing such non-generically reusable improvements and restoring the affected area of the Premises to the condition indicated by Exhibit B-1. Landlord shall respond to such request for revisions within five (5) Business Days.

C. This Exhibit shall not be deemed applicable to any additional space added to the Premises at any time or from time to time, whether by any options under the Lease or otherwise, or to any portion of the original Premises or any additions to the Premises in the event of a renewal or extension of the original Term of the Lease, whether by any options under the Lease or otherwise, unless expressly so provided in the Lease or any amendment or supplement to the Lease.

Exhibit B, Fourth Amendment

Page 2

EXHIBIT B-1

PLANS

Exhibit B-1, Fourth Amendment

EXHIBIT C

TENANT’S RESERVED PARKING SPACES

Exhibit C, Fourth Amendment

EXHIBIT D

RIGHTS OF OTHERS PRIOR TO TENANT’S ROFO RIGHTS

NONE

Exhibit D, Fourth Amendment

EXHIBIT E

FORM OF SNDA

SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT

                                                     ,

Tenant

AND

CANADIAN IMPERIAL BANK OF COMMERCE,

acting through its New York Branch,

as Administrative Agent

County:	Middlesex
State:	Massachusetts
Premises:	41 Seyon Street, 43 Foundry
	Avenue and 190 Willow Street Waltham, Massachusetts

Dated: as of                         , 201    

Record and return by mail to:

Morrison & Foerster LLP

1290 Avenue of the Americas

New York, New York 10104

Attention: Christopher S. Delson, Esq.

Exhibit E, Fourth Amendment

SUBORDINATION, NON-DISTRURBANCE AND ATTORNMENT AGREEMENT

THIS AGREEMENT made as of this      day of                     , 201    , by and among                         (“Landlord’), CANADIAN IMPERIAL BANK OF COMMERCE, acting through its New York Branch (“Administrative Agent”), as Administrative Agent for the Lenders (defined below), and                         (“Tenant”).

RECITALS:

A. Tenant has executed that certain lease dated                         [as amended by written agreements dated                         and                         ] ([collectively, with the amendment{s} thereto,] the “Lease”), with [                        , predecessor-in-title to] Landlord, as lessor, covering the premises described in the Lease consisting of approximately a                     square foot space (the “Premises”) in that certain building located at [                        ]¹ Waltham, Massachusetts (the “Property”) and more particularly described in Exhibit A attached hereto and made a part hereof by this reference; and

B. Certain lenders (the “Lenders”) have made (or agreed to make) a loan to Landlord secured by a mortgage encumbering the Property and an assignment of Landlord’s interest in the Lease (said mortgage, together with any amendments, renewals, increases, modifications, substitutions or consolidations of either of them, collectively, the “Security Instrument”) in favor of Administrative Agent on behalf of the Lenders; and

C. Tenant and Administrative Agent desire to confirm their understanding with respect to the Lease and the Security instrument, and to have Landlord confirm its agreement therewith.

NOW, THEREFORE, in consideration of the covenants, terms, conditions, and agreements contained herein, the parties hereto agree as follows:

1. The Lease and any extensions, modifications or renewals thereof, including but not limited to any option to purchase, right of first refusal to purchase or right of first offer to purchase the Property or any portion thereof, if any, is and shall continue to be subject and subordinate in all respects to the Security Instrument and the lien created thereby.

2. Tenant agrees to deliver to Administrative Agent, in the manner set forth in Paragraph 13 of this Agreement, a copy of any notice of default sent to Landlord by Tenant. If Landlord fails to cure such default within the time provided in the lease, Administrative Agent shall have the right, but not the obligation, to cure such default on behalf of Landlord within thirty (30) calendar days after the time provided for Landlord to cure such default in the Lease has expired or, if such default cannot be cured within that time, within a reasonable period provided Administrative Agent is proceeding with due diligence to cure such default. In such event, Tenant shall not terminate the Lease while such remedies are being diligently pursued by Administrative Agent. Further, Tenant shall not terminate the Lease on the basis of any default by Landlord which is incurable by Administrative Agent (such as, for example, the bankruptcy of Landlord or breach of any representation by Landlord), provided Administrative Agent is proceeding with due diligence to commence an action to appoint a receiver or to obtain title to the Property by foreclosure, deed in lieu of foreclosure, or otherwise (collectively, “Foreclosure”). Subject to Administrative Agent’s obligations under Section 3 below, Tenant hereby agrees that no action taken by Administrative Agent to enforce any rights under the Security Instrument or related security documents, by reason of any default thereunder

¹  Insert as applicable: 41 Seyon Street, 43 Foundry Avenue or 190 Willow Street

Exhibit E, Fourth Amendment

(including, without limitation, the appointment of a receiver, any Foreclosure or any demand for rent under any assignment of rents or leases) shall give rise to any right of Tenant to terminate the Lease nor shall such action invalidate or constitute a breach of any of the terms of the Lease.

3. So long as Tenant is not in default under the Lease beyond applicable notice and cure periods, Administrative Agent shall not disturb Tenant’s possession and occupancy of the Premises and Tenant’s other rights under the Lease during the term of the Lease.

4. If Administrative Agent or its nominee or designee, or another purchaser of the Property upon a Foreclosure (any such person or entity, a “Successor Owner”) succeeds to the interest of Landlord under the Lease, subject to Tenant’s performance of its obligations under the Lease within applicable notice and cure periods, the Lease will continue in full force and effect. Thereupon, Successor Owner shall recognize the Lease and Tenant’s rights thereunder and Tenant shall make full and complete attornment to Successor Owner as substitute landlord upon the same terms, covenants and conditions as provided in the Lease, including, but not limited to, any option to purchase, right of first refusal to purchase or right of first offer to purchase the Property as may be provided in the Lease. Notwithstanding the foregoing, Tenant agrees that any such option, right of first refusal or right of first offer to purchase the Property or any portion thereof, as may be provided in the Lease shall not apply to any Foreclosure, as defined herein, and shall not apply to any transfer of the Property by Successor. Owner following such Forecloser. In consideration of the foregoing, Administrative Agent agrees that any such option, right of first refusal or right of first offer shall not be terminated by any Foreclosure or conveyance of the Property by Successor Owner following such Foreclosure; rather, any such option, right of first refusal or right of first offer shall remain as an obligation of any party acquiring the Property following the conveyance of the Property by Successor Owner following such Foreclosure. Furthermore, Tenant expressly confirms to Administrative Agent that any acquisition of title to all or any portion of the Property pursuant to Tenant’s exercise of any option, right of first refusal or right of first offer contained in the Lease shall result in Tenant taking title subject to the lien of the Security Instrument.

5. Tenant agrees that, if Successor Owner shall succeed to the interest of Landlord under the Lease, Successor Owner shall not be:

(a) liable for any prior act or omission of Landlord or any prior landlord or consequential damages arising therefrom; or

(b) subject to any offsets or defenses which Tenant might have as to Landlord or any prior landlord unless Administrative Agent has failed to cure any default by Landlord as herein provided; or

(c) required or obligated to credit Tenant with any rent or additional rent for any rental period beyond the then current month which tenant might have paid Landlord; or

(d) bound by any amendments or modifications of the Lease made without Administrative Agent’s or Successor Owner’s prior written consent; or

(e) liable for refund of all or any part of any security deposit unless such security deposit shall have been actually received by Administrative Agent.

Exhibit E, Fourth Amendment

6. Tenant agrees that, without the prior written consent of Administrative Agent in each case, Tenant shall not (a) amend, modify, terminate or cancel the Lease or any extensions or renewals thereof, or tender a surrender of the Lease (except in each case that, upon a default by Landlord under the Lease, Tenant may exercise its rights under the Lease after giving to Administrative Agent the notice and cure period required by this Agreement), (b) make a prepayment of any rent or additional rent more than one (1) month in advance of the due date thereof, or (c) subordinate or permit the subordination of the Lease to any lien subordinate to the Security Instrument. Any such purported action without such consent shall be void as against the holder of the Security Instrument.

7. To the extent that the Lease shall entitle Tenant to notice of the existence of any Security Instrument and the identity of any mortgagee or any ground lessor, this Agreement shall constitute such notice to Tenant with respect to the Security Instrument and Administrative Agent.

8. Upon and after the occurrence of a default under the Security Instrument, which is not cured after any applicable notice and/or cure periods, Administrative Agent shall be entitled, but not obligated, to require that Tenant pay all rent under the Lease as directed by Administrative Agent, which payment shall, to the extent made, satisfy the obligations of Tenant under the Lease. Landlord agrees to hold Tenant harmless with respect to any such payments made by Tenant to Administrative Agent.

9. Nothing in this Agreement shall impose upon Administrative Agent any liability for the obligations of Landlord under the Lease unless and until Administrative Agent takes title to the Property. Anything herein or in the Lease to the contrary notwithstanding, in the event that a Successor Owner shall acquire title to the Property or the portion thereof containing the Premises, Successor Owner shall have no obligation, nor incur any liability, beyond Successor Owner’s then interest, if any, in the Property, and Tenant shall look exclusively to such interest, if any, of Successor Owner in the Property for the payment and discharge of any obligations imposed upon Successor Owner hereunder or under the Lease, and Successor Owner is hereby released or relieved of any other liability hereunder and under the Lease. Tenant agrees that, with respect to any money judgment which may be obtained or secured by Tenant against Successor Owner, Tenant shall look solely to the estate or interest owned by Successor Owner in the Property, and Tenant will not collect or attempt to collect any such judgment out of any other assets of Successor Owner.

10. Except as specifically provided in this Agreement, Administrative Agent shall not, by virtue of this Agreement, the Security Instrument or any other instrument to which Administrative Agent may be party, be or become subject to any liability or obligation to Tenant under the Lease or otherwise.

11. EACH OF TENANT, ADMINISTRATIVE AGENT AND LANDLORD HEREBY IRREVOCABLY WAIVE ALL RIGHT TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR RELATING TO THIS AGREEMENT.

12. The provisions of the Agreement shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns. The words, “Administrative Agent”, “Landlord” and “Tenant” shall include their respective heirs, legatees, executors, administrators, beneficiaries, successors and assigns.

Exhibit E, Fourth Amendment

13. All notices and all other communication with respect to this Agreement shall be directed as follows: if to Administrative Agent, 200 West Madison Avenue, Suite 2610, Chicago, Illinois 60606, Attention: Real Estate Group, or such other address as Administrative Agent may designate in writing to Tenant; and, if to Tenant, at the address set forth in the Lease or at such other address as tenant may designate in writing to Administrative Agent. All notices shall be in writing and shall be (a) hand-delivered, (b) sent by United States express mail or by private overnight courier, or (c) served by certified mail postage prepaid, return receipt requested, to the appropriate address set forth above. Notices served as provided in (a) and (b) shall be deemed to be effective upon delivery or upon refusal thereof. Any notice served by certified mail shall be deposited in the United States mail with postage thereon fully prepaid and shall be deemed effective on the day of actual delivery as shown by the addressee’s return receipt or the expiration of three business days after the date of mailing, whichever is earlier in time.

14. This Agreement contains the entire agreement between the parties and no modifications shall be binding upon any party hereto unless set forth in a document duly executed by or on behalf of such party.

15. This Agreement may be executed in multiple counterparts, all of which shall be deemed originals and with the same effect as if all parties had signed the same document. All of such counterparts shall be construed together and shall constitute one instrument.

[Remainder of Page Intentionally Left Blank; Signature Page Follows]

Exhibit E, Fourth Amendment

IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement as of the day and year first above written.

CANADIAN IMPERIAL BANK OF COMMERCE, acting through its New York Branch, as Administrative Agent for the Lenders
By:
	Name:
	Title:

Exhibit E, Fourth Amendment

[TENANT]
By:
	Name:
	Title:

Exhibit E, Fourth Amendment

AGREED AND CONSENTED TO:

LANDLORD

CENTERPOINT ACQUISITIONS, LLC,

a Delaware limited liability & company

Exhibit E, Fourth Amendment

ACKNOWLEDGEMENT

STATE OF	)
		) SS.
COUNTY OF	)

On the         day of                 in the year 201    , before me, the undersigned, personally appeared                 , personally known to me or proved to me on the basis of satisfactory evidence to be the individual whose name is subscribed to the within instrument and acknowledged to me that [s/he] executed the same in his capacity as Authorized Signatory, of CANADIAN IMPERIAL BANK OF COMMERCE, acting through its New York Branch as Administrative Agent for the Lenders, and that by [her/his] signature on the instrument, the individual, or the person upon behalf of which the individual acted, executed the instrument.

Notary Public

My commission expires:

Exhibit E, Fourth Amendment

ACKNOWLEDGEMENT

STATE OF	)
	) SS.
COUNTY OF	)

I, a Notary Public in and for said County, in the State aforesaid, DO HEREBY CERTIFY that                 as                 of CENTERPOINT ACQUISITIONS, LLC, a Delaware limited liability company, appeared before me this day in person and acknowledged that he signed and delivered said instrument as his own free and voluntary act and as the free and voluntary act of said entities for the uses and purposes therein set forth.

Notary Public

My commission expires:

Exhibit E, Fourth Amendment

ACKNOWLEDGEMENT

STATE OF	)
		) SS.
COUNTY OF	)

I, a Notary Public in and for said County, in the State aforesaid, DO HEREBY CERTIFY that                 as                 of                 , a                      appeared before me this day in person and acknowledged that he signed and delivered said instrument as his own free and voluntary act and as the free and voluntary act of said                     , for the uses and purposes therein set forth.

Notary Public

My commission expires:

Exhibit E, Fourth Amendment

EXHIBIT A

Legal Description of Property

Lot A (UNREGISTERED LAND)

A certain parcel of land in Waltham, Middlesex County, Massachusetts, westerly of Seyon Street, northerly of Boston and Maine Railroad, easterly of Willow Street and southerly of Grove Street, being shown as Lot A on a plan entitled “CenterPoint Project Merger of Plan of Land in Waltham, Massachusetts, Middlesex County”, dated January 28, 2013, prepared by DGT Survey Group, to be recorded with Middlesex South Registry of Deeds herewith, and being more particularly described as follows:

Beginning at the intersection of the westerly side of Seyon Street with the northerly side of the former Boston and Maine railroad location, thence running:

N 52-08-34 W	203.28 feet	to a point of curvature; thence
Westerly	20.00 feet	by a curve to the left of 1750.76 foot radius to a point of non-tangency, the last two courses being by land now or formerly of Boston & Maine Corporation; thence
S 37-12-10 W	16.50 feet	in part by said land of the former Boston & Maine Corporation and in part by land now or formerly of Colonial Shopping Center, Inc. to a point of non-tangency; thence
Westerly	119.43 feet	by a curve to the left of 1734.26 foot radius to a point of compound curvature, being by said land of Colonial Shopping Center; thence
Westerly	457.86 feet	by a curve to the left of 1121.09 foot radius to a point of non-tangency, being in part by said land of Colonial Shopping Center, Inc. and in part by land now or formerly of Anthony G. Cardillo, Jr. and Joseph J. Cardillo; thence
N 78-04-22 W	25.15 feet	thence
N 73-45-26 W	66.87 feet	to a point of non-tangency, the last two courses being by said land of Anthony G. Cardillo, Jr. et al; thence
Westerly	114.07 feet	by a curve to the left of 1310.85 foot radius to a point of non-tangency; thence
N 85-43-49 W	110.48 feet	to a point of non-tangency; thence
Westerly	21.28 feet	by a curve to the left of 1318.10 foot radius to a point of tangency; thence
S 87-10-56 W	53.54 feet	to the easterly side of Willow Street, the last four courses being by land now or formerly of Sadle M. Cardillo and Anthony G. Cardillo, Jr.; the last eleven courses being also by said Boston and Maine railroad location; thence

Exhibit B-1 Fourth Amendment

N 26-44-06 E	172.66 feet	by Willow Street; thence
S 63-36-26 E	35.87 feet	by land now or formerly of Raytheon Company; thence
S 62-06-32 E	64.14 feet	thence
N 26-44-06 E	1.68 feet	the last two courses being by land now or formerly of Willow Street Trust; thence
S 63-36-26 E	2.07 feet	thence
N 25-08-10 E	73.58 feet	thence
N 63-36-26 W	100.02 feet	to the easterly side of Willow Street, the last three courses being by land of said Raytheon Company; thence
N 26-44-06 E	185.87 feet	by Willow Street to a point of curvature at Foundry Avenue; thence
Easterly	15.60 feet	by a curve to the right of 10.00 foot radius to a point of non-tangency; thence
S 63-52-04 E	454.36 feet	the last two courses being by the southerly side of Foundry Avenue; thence
N26-07-56 E	40.00 feet	by the easterly end of Foundry Avenue; thence
N 63-52-04 W	192.40 feet	by the northerly side of Foundry Avenue; thence
N 26-17-50 E	293.83 feet	in part by land now or formerly of John Sottile, in part by land now or formerly of Noviens Lane Nominee Trust, in part by the easterly end of Noviens Lane, in part by land now or formerly of Pak Chau Chan and Chan Vuong and in part by land now or formerly of Anjo Realty Trust; thence
S 62-14-54 E	250.01 feet	thence
S 62-14-54 E	32.02 feet	thence
S 63-59-24 E	8.00 feet	thence
S 62-54-32 E	316.29 feet	to a stone bound with drill hole; thence
N 25-58-32 E	619.17 feet	to the southerly side of Grove Street, the last five courses being by land now or formerly of Standard Thomson Corporation; thence
S 67-07-36 E	516.92 feet	to a point of curvature; thence
Easterly	90.21 feet	by a curve to the left of 1942.98 foot radius to a rounding at Seyon Street, the last two courses being by Grove Street; thence
Easterly and southerly	59.26 feet	by a curve to the right of 30.00 foot radius by said rounding at Seyon Street to the westerly side of Seyon Street; thence
S 43-23-26 W	753.60 feet	thence
S 40-33-56 W	553.97 feet	to the point of beginning, the last two courses being by Seyon Street.

TOGETHER WITH rights contained in the following:

A. Bridge Switchgear and Fire Loop Easement Agreement dated February 28, 2001 recorded with said Deeds in Book 32455, Page 291 and filed with said Land Court as Document No. 1164263; as affected by First Amendment to Bridge, Switchgear and Fire Loop Easement Agreement dated December 16, 2005 recorded with said Deeds in Book 46700, Page 38.

Exhibit E, Fourth Amendment

B. Grant of Easement made by and among Colonial Shopping Center, Inc., I-Park West Seyon LLC and Raytheon Company dated November 17, 2005 recorded with said Deeds in Book 46652, Page 431.

C. Access Easement Agreement made by and between Grove Willow LLC and Raytheon Company dated as of December 30, 1999 and recorded with said Deeds in Book 31018, Page 1 as affected by the following:

Amendment to Access Easement Agreement dated December 19, 2005 and recorded with said Deeds in book 46712, Page 292.

Second Amendment to Access Easement Agreement dated December 18, 2007 and recorded with said Deeds in Book 50547, Page 37.

Affidavit dated December 31, 2007 and recorded with said Deeds in Book 50547, Page 40.

Amendment to Access Easement Agreement concerning 3.46 Acre Parcel dated March 27, 2008 and recorded with said Deeds in Book 51404, Page 1.

Amendment to Access Easement Agreement Concerning LIG Parcel dated April 3, 2008 and recorded with said Deeds in Book 52219, Page 319.

Third Amendment to Access Easement Agreement dated June 12, 2009 and recorded with said Deeds in Book 53017, Page 468.

Exhibit E, Fourth Amendment

EX-31.1

Exhibit 31.1

CERTIFICATION

I, Walter C. Herlihy, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Repligen Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: May 9, 2014

/S/    WALTER C. HERLIHY        

Walter C. Herlihy

President and Chief Executive Officer

(Principal executive officer)

EX-31.2

Exhibit 31.2

CERTIFICATION

I, William J. Kelly, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Repligen Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

(a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

(d) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: May 9, 2014

/S/    WILLIAM J. KELLY        

William J. Kelly

Chief Accounting Officer

(Principal financial officer)

EX-32.1

Exhibit 32.1*

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Repligen Corporation (the “Company”) on Form 10-Q for the period ending March 31, 2014 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned officers of the Company hereby certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, to my knowledge, that:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: May 9, 2014	By:	/S/    WALTER C. HERLIHY
		Walter C. Herlihy
		Chief Executive Officer and President
		(Principal executive officer)
Date: May 9, 2014	By:	/S/    WILLIAM J. KELLY
		William J. Kelly
		Chief Accounting Officer
		(Principal financial officer)

* This certification shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section, nor shall it be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934.

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Investments in Money Market Funds and Marketable Securities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 32,459,013	$ 34,017,451
Gross Unrealized Gain	8,889	4,637
Gross Unrealized Loss	(11,986)	(9,936)
Fair Value	32,455,916	34,012,152
Marketable securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,546,789	21,792,154
Gross Unrealized Gain	6,458	4,071
Gross Unrealized Loss	(1,849)	(2,675)
Fair Value	21,551,398	21,793,550
Marketable securities | U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,529,909	8,165,464
Gross Unrealized Gain	2,415	435
Gross Unrealized Loss	(120)	(630)
Fair Value	9,532,204	8,165,269
Marketable securities | Corporate and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,016,880	13,626,690
Gross Unrealized Gain	4,043	3,636
Gross Unrealized Loss	(1,729)	(2,045)
Fair Value	12,019,194	13,628,281
Long-term marketable securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,912,224	12,225,297
Gross Unrealized Gain	2,431	566
Gross Unrealized Loss	(10,137)	(7,261)
Fair Value	10,904,518	12,218,602
Long-term marketable securities | U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,918,120	11,599,415
Gross Unrealized Gain	516	466
Gross Unrealized Loss	(8,279)	(7,034)
Fair Value	8,910,357	11,592,847
Long-term marketable securities | Corporate and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,994,104	625,882
Gross Unrealized Gain	1,915	100
Gross Unrealized Loss	(1,858)	(227)
Fair Value	$ 1,994,161	$ 625,755

XML

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended				3 Months Ended					12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2014 Income Before Income Tax	Mar. 31, 2013 Income Before Income Tax	Mar. 31, 2014 Income Tax Provision	Mar. 31, 2013 Income Tax Provision	Mar. 31, 2014 Maximum	Dec. 31, 2013 Sweden	Mar. 31, 2014 Available to Reduce Future Federal Income Taxes
Income Taxes [Line Items]
Income before income taxes	$ 5,398,105	$ 3,622,068			$ 5,398,000	$ 3,622,000
Income tax provision	1,121,002	1,283,832					1,121,000	1,284,000
Expected effective tax rate				20.90%
Discrete items recognized		298,000
Effective tax rate	20.80%	35.45%
Effective statutory tax rate										28.21%
Net operating loss carry forwards											37,633,000
Business tax credit carry forwards											1,520,000
Net operating loss and business tax credit carry forwards expiration date									At various dates through December 2031
Reversed of deferred tax asset valuation allowance			$ 3,021,000

XML

Schedule of Accrued Liabilities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Schedule of Accrued Liabilities [Line Items]
Employee compensation	$ 2,228,965	$ 3,166,086
Taxes	655,703	2,324,711
Royalty and license fees	560,501	1,897,473
Contingent consideration (current portion)	1,313,145	1,195,248
Unearned revenue		3,341
Professional fees	402,820	385,478
VAT liabilities		7,591
Other accrued expenses	477,801	599,784
Total	$ 5,638,935	$ 9,579,712

XML

Earnings Per Share - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Earnings Per Share [Line Items]
Stock options, outstanding	1,675,077	2,231,590	1,610,988
Stock options, weighted average exercise price	$ 5.78	$ 4.40	$ 5.07
Common stock excluded from calculation of diluted earnings per share	207,431	516,500

XML

Inventories (Tables)

3 Months Ended

Mar. 31, 2014

Schedule of Inventories

Inventories consist of the following:

	March 31, 2014		December 31, 2013
Raw materials	$	4,224,034	$	4,557,870
Work-in-process		3,032,739		4,285,648
Finished products		4,184,544		2,955,120
Total	$	11,441,317	$	11,798,638

XML

Percentage of Revenue by Geographic Area (Detail) (Total Revenue)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Concentration Risk [Line Items]
Revenues, percentage by country	100.00%	100.00%
United States
Concentration Risk [Line Items]
Revenues, percentage by country	49.00%	47.00%
Sweden
Concentration Risk [Line Items]
Revenues, percentage by country	32.00%	39.00%
United Kingdom
Concentration Risk [Line Items]
Revenues, percentage by country	18.00%	12.00%
Other
Concentration Risk [Line Items]
Revenues, percentage by country	1.00%	2.00%

XML

Fair Value Measurement - Additional Information (Detail) (USD $)		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013 Novozymes Biopharma DK A/S Sweden Ab	Mar. 31, 2013 Novozymes Biopharma DK A/S Sweden Ab Milestone Payments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of other assets	$ 0
Fair value of other liabilities	0
Business acquisition, contingent payment			80,000
Fair value adjustment		$ 92,000

XML

Summary of Information Regarding Option Activity (Parenthetical) (Detail) (Employee Stock Option)	Mar. 31, 2014
Awards Granted to Non-Executive Level Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated forfeiture rates	8.00%
Awards Granted to Executive Level Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated forfeiture rates	3.00%

XML

Percentage of Accounts Receivable by Significant Customers (Detail) (Accounts Receivable)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Orencia Royalties from Bristol
Concentration Risk [Line Items]
Accounts receivable, percentage by customer		42.00%
Bioprocessing Customer A
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	58.00%	17.00%
Bioprocessing Customer B
Concentration Risk [Line Items]
Accounts receivable, percentage by customer	22.00%	8.00%
Tenant improvement allowance due from landlord
Concentration Risk [Line Items]
Accounts receivable, percentage by customer		15.00%

XML

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended
	Mar. 31, 2014
Commitments and Contingencies [Line Items]
Lease agreement, term	8 years 1 month
Operating leases, rent expense	$ 361,000
Future minimum rental commitment, reminder of 2014	908,000
Future minimum rental commitment, 2015	1,371,000
Future minimum rental commitment, 2016	1,371,000
Future minimum rental commitment, 2017	1,371,000
Future minimum rental commitment, 2018	1,371,000
Before Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space	55,694
Security deposit	200,000
After Amendment
Commitments and Contingencies [Line Items]
Lease agreement, space	75,594
Security deposit	$ 450,000
Expansion Space
Commitments and Contingencies [Line Items]
Lease agreement, space	19,900

XML

Accumulated Other Comprehensive Income

3 Months Ended

Mar. 31, 2014

Accumulated Other Comprehensive Income

4. Accumulated Other Comprehensive Income

The following table summarizes the changes in accumulated other comprehensive income by component:

(In thousands)	Unrealized gain (loss) on investments			Foreign currency translation gain (loss)			Total
Balance at December 31, 2013	$	(5,281	)	$	2,003,611		$	1,998,330
Other comprehensive income before reclassifications		2,184			(143,153	)		(140,969	)
Amounts reclassified from accumulated other comprehensive income		—			—			—
Net current period other comprehensive income		2,184			(143,153	)		(140,969	)
Balance at March 31, 2014	$	(3,097	)	$	1,860,458		$	1,857,361

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Roll Forward of Fair Value of Contingent Consideration (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013	$ 1,648,928
Additions
Payments	(80,000)
Changes in fair value	97,777
Balance at March 31, 2014	$ 1,666,705

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Intangible Assets (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,567,967	$ 8,592,434
Accumulated Amortization	(2,652,862)	(2,404,802)
Weighted Average Useful Life (in years)	8 years	8 years
Technology - developed
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,453,006	1,455,382
Accumulated Amortization	(581,084)	(537,589)
Weighted Average Useful Life (in years)	8 years	8 years
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	240,000	240,000
Accumulated Amortization	(125,000)	(117,500)
Weighted Average Useful Life (in years)	8 years	8 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,874,961	6,897,052
Accumulated Amortization	$ (1,946,778)	$ (1,749,713)
Weighted Average Useful Life (in years)	8 years	8 years

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Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Business Acquisition [Line Items]
Goodwill impairment	$ 0
Amortization expense	248,000
Expected amortization expense in 2014	1,000,000
Expected amortization expense in 2015	1,000,000
Expected amortization expense in 2016	1,000,000
Expected amortization expense in 2017	1,000,000
Expected amortization expense in 2018	$ 1,000,000

XML

Inventories - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Inventory [Line Items]
Reserves for excess and obsolete inventory	$ 182,000	$ 183,000

XML

Revenue Recognition - Additional Information (Detail) (USD $)	3 Months Ended				3 Months Ended	1 Months Ended		3 Months Ended		12 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Clinical Development	Mar. 31, 2014 Initial Commercial Sales	Mar. 31, 2014 Technology Transfer	Sep. 30, 2013 Pfizer Incorporation Nonsoftware License Arrangement	Jan. 31, 2013 Pfizer Incorporation Nonsoftware License Arrangement	Mar. 31, 2014 Pfizer Incorporation Nonsoftware License Arrangement	Mar. 31, 2013 Pfizer Incorporation Nonsoftware License Arrangement	Dec. 31, 2012 Pfizer Incorporation Nonsoftware License Arrangement	Mar. 31, 2014 Orencia Royalties from Bristol	Mar. 31, 2013 Orencia Royalties from Bristol	Jan. 30, 2014 BioMarin Pharmaceutical, Inc. Asset Purchase Agreement	Mar. 31, 2014 BioMarin Pharmaceutical, Inc. Asset Purchase Agreement	Mar. 31, 2014 BioMarin Pharmaceutical, Inc. Asset Purchase Agreement Clinical Development	Mar. 31, 2014 BioMarin Pharmaceutical, Inc. Asset Purchase Agreement Initial Commercial Sales
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Upfront Payment received under license agreement							$ 5,000,000						$ 2,000,000
Potential milestone payments to be received			60,000,000	100,000,000										160,000,000
Percentage relate to clinical development from Milestone payment															37.00%	63.00%
Provision for refund														0
License agreement, revenue recognized	2,115,000				0			0	55,000	4,876,000				2,000,000
Non-refundable up-front payment	2,000,000
Payment to be received upon signing of agreement	126,375
Revenue recognized under revenue recognition, up front payment	2,000,000
Estimated selling price					300,000
Consideration allocated to transaction					11,000
Milestone Payment			60,000,000			1,000,000
Potential milestone payments to be received								64,000,000
Royalty revenue	1,991,166	4,521,724									0	3,846,000
Percentage of royalty revenue, remittance to the University of Michigan	15.00%
Cost of royalty and other revenue		576,857									0	577,000
Revenue from sponsored research and development projects	$ 0	$ 621,000

XML

Changes in Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2013	$ 1,998,330	$ 1,857,361	$ 1,998,330
Other comprehensive income before reclassifications	(140,969)
Amounts reclassified from accumulated other comprehensive income
Net current period other comprehensive income	(140,969)
Balance at March 31, 2014	1,857,361	1,857,361	1,998,330
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2013	(5,281)
Other comprehensive income before reclassifications	2,184
Amounts reclassified from accumulated other comprehensive income
Net current period other comprehensive income	2,184
Balance at March 31, 2014	(3,097)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at December 31, 2013	2,003,611
Other comprehensive income before reclassifications	(143,153)
Amounts reclassified from accumulated other comprehensive income
Net current period other comprehensive income	(143,153)
Balance at March 31, 2014	$ 1,860,458

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Revenue Recognition

3 Months Ended

Mar. 31, 2014

Revenue Recognition

3. Revenue Recognition

Product Sales

The Company generates revenue from the sale of products. Historically, the Company also generated revenue from licensing transactions and research and development collaborations. The Company’s product revenues are from the sale of bioprocessing products to customers in the life science and biopharmaceutical industries. Revenue related to product sales is recognized upon delivery of the product to the customer as long as there is persuasive evidence of an arrangement, the sales price is fixed or determinable and collection of the related receivable is reasonably assured. Determination of whether these criteria have been met are based on management’s judgments primarily regarding the fixed nature of the fee charged for the product delivered and the collectability of those fees. The Company has a few longstanding customers who comprise the majority of revenue and have excellent payment histories and therefore the Company does not require collateral. The Company has had no significant write-offs of uncollectible invoices in the periods presented.

At the time of sale, the Company also evaluates the need to accrue for warranty and sales returns. The supply agreements the Company has with its customers and the related purchase orders identify the terms and conditions of each sale and the price of the goods ordered. Due to the nature of the sales arrangements, inventory produced for sale is tested for quality specifications prior to shipment. Since the product is manufactured to order and in compliance with required specifications prior to shipment, the likelihood of sales return, warranty or other issues is largely diminished. Sales returns and warranty issues are infrequent and have had nominal impact on the Company’s financial statements historically.

Sale of Intellectual Property to BioMarin

In January 2014, the Company entered into an asset purchase agreement (the “Asset Purchase Agreement”) with BioMarin Pharmaceutical Inc. (“BioMarin”) to sell Repligen’s histone deacetylase inhibitor (HDACi) portfolio. Pursuant to the terms of the Asset Purchase Agreement, the Company received $2 million from BioMarin as an upfront payment on January 30, 2014. The Company is entitled to receive up to $160 million in potential future milestone payments for the development, regulatory approval and commercial sale of portfolio compounds included in the agreement. These potential milestone payments are approximately 37% related to clinical development and 63% related to initial commercial sales in specific geographies. In addition, Repligen is eligible to receive royalties on sales of therapeutic products originating from the HDACi portfolio. The royalty rates are tiered and begin in the mid-single-digits for the first HDACi portfolio product and for the first non-HDACi portfolio product with lesser amounts for any backup products developed under the Asset Purchase Agreement. Repligen’s receipt of these royalties is subject to customary offsets and deductions. There are no refund provisions in this agreement. The Company recognized $2 million of revenue in the three months ended March 31, 2014 related to the transfer of the HDACi technology under the Asset Purchase Agreement. Any milestones earned upon specified clinical development or commercial sales events or future royalty payments, under the Asset Purchase Agreement will be recognized as revenue when they are earned.

Activities under this agreement were evaluated in accordance with ASC 605-25 to determine if they represented a multiple element revenue arrangement. We identified the following deliverables in the BioMarin agreement:

• The assignment by Repligen to BioMarin of the Repligen Technology (“Repligen Know-How” and “Repligen Patents”) and the Scripps Agreement (the “Transferred Assets”);

• The transfer of certain notebooks, data, documents, biological materials (if any) and other such documents in our possession that might be useful to further development of the program (the “Technology Transfer”).

Two criteria must be met in order for a deliverable to be considered a separate unit of accounting. The first criterion requires that the delivered item or items have value to the customer on a stand-alone basis. The second criterion, which relates to evaluating a general right of return, is not applicable because such a provision does not exist in the Asset Purchase Agreement. The deliverables outlined above were deemed to have stand-alone value and to meet the criteria to be accounted for as separate units of accounting. Factors considered in this determination included, among other things, BioMarin’s right under the agreement to assign the Transferred Assets, whether any other vendors sell the items separately and if BioMarin could use the delivered item for its intended purpose without the receipt of the remaining deliverables. If multiple deliverables included in an arrangement are separable into different units of accounting, the multiple-element arrangements guidance addresses how to allocate the arrangement consideration to those units of accounting. The amount of allocable arrangement consideration is limited to amounts that are fixed or determinable. Arrangement consideration is allocated at the inception of the arrangement to the identified units of accounting based on their relative selling price.

We identified the arrangement consideration to allocate among the units of accounting as the $2.0 million non-refundable up-front payment and the $126,375 payment to be received upon completion of the Technology Transfer. We excluded the potential milestone payments provided for in the Asset Purchase Agreement from the arrangement consideration as they were not considered fixed or determinable at the time the Asset Purchase Agreement was signed. Because we had not sold these items on a standalone basis previously, we had no vendor-specific objective evidence of selling price. Furthermore, we did not have detailed third-party evidence of selling price, and as a result we used our best estimate of selling price for each item. In determining these prices, we considered what we would be willing to sell the items for on a standalone basis, what the market would bear for such items and what another party might charge for these items.

The up-front arrangement consideration allocated to the Transferred Assets was recognized upon execution of the Asset Purchase Agreement as the risks and rewards associated with the Transferred Assets transferred at that time. We used a discounted cash flow analysis to determine the value of the Transferred Assets. Key assumptions in the analysis included: the estimated market size for a compound targeted at Friedreich’s ataxia, the estimated remaining costs of development and time to commercialization, and the probability of successfully developing and commercializing the program. Based on this analysis, we allocated $2,115,000 to the value of the Transferred Assets. However, as the recognize revenue is limited to the non-contingent consideration received, we recognized $2,000,000, the amount of the up-front payment, as revenue in the three months ended March 31, 2014.

The estimated selling price of the Technology Transfer items was approximately $300,000 resulting in consideration allocation of approximately $11,000. However, as this item was not delivered prior to March 31, 2014, we did not recognize any revenue related to the Technology Transfer in the three months ended March 31, 2014. We expect the Technology Transfer to be delivered by June 30, 2014.

We believe that a change in the key assumptions used to determine best estimate of selling price for each of the deliverables would not have a significant effect on the allocation of arrangement consideration.

In addition to the $2 million up-front payment, we are also eligible to receive up to $160 million in potential milestone payments from BioMarin comprised of:

• Up to $60 million related to the achievement of specified clinical and regulatory milestone events; and

• Up to $100 million related to the achievement of specified commercial sales events, specifically the first commercial sale in specific territories.

We evaluated the potential milestones in accordance with ASC 605-28, which allows an entity to make an accounting policy election to recognize a payment that is contingent upon the achievement of a substantive milestone in its entirety in the period in which the milestone is achieved. This evaluation included an assessment of the risks that must be overcome to achieve the respective milestone as well as whether the achievement of the milestone was due in part to our initial clinical work, the level of effort and investment required to achieve the respective milestone and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement. There is considerable judgment involved in determining whether a milestone satisfies all of the criteria required to conclude that a milestone is substantive. Milestones that are not considered substantive are recognized as earned if there are no remaining performance obligations or over the remaining period of performance, assuming all other revenue recognition criteria are met.

We believe that the $60 million of specified clinical and regulatory milestone payments are substantive. Therefore, any such milestones achieved will be recognized as revenue when earned.

Any milestones achieved upon specified commercial sales events or future royalty payments are considered contingent revenue under the Asset Purchase Agreement, and will be recognized as revenue when they are earned as there are no undelivered elements remaining and no continuing performance obligations under the arrangement.

Pfizer License Agreement

In December 2012, the Company entered into an exclusive worldwide licensing agreement (the “License Agreement”) with Pfizer Inc. (“Pfizer”) to advance the spinal muscular atrophy program, or SMA program. Pursuant to the terms of the License Agreement, the Company received $5 million from Pfizer as an upfront payment on January 22, 2013 and a $1 million milestone payment on September 4, 2013. The Company is entitled to receive up to $64 million in potential future payments, a portion of which may be owed to third parties. These potential payments are approximately equally divided between milestones related to clinical development and initial commercial sales in specific geographies. In addition, the Company is entitled to receive royalties on any future sales of RG3039 or any SMA compounds developed under the License Agreement. The royalty rates are tiered and begin in the high single-digits for RG3039 or lesser amounts for any backup compounds developed under the License Agreement. Repligen’s receipt of these royalties is subject to an obligation under an existing in-license agreement and other customary offsets and deductions. There are no refund provisions in this agreement. The Company recognized $4,876,000 of revenue related to the value of the license in the year ended December 31, 2012. The Company recognized $0 and $55,000 of revenue in the three months ended March 31, 2014 and 2013, respectively, related to the delivery of clinical and transition services under the License Agreement. Any milestones earned upon specified commercial sales events or future royalty payments, under the License Agreement will be recognized as revenue when they are earned.

Orencia Royalty

In April 2008, the Company settled its outstanding litigation with Bristol-Myers Squibb Company (“Bristol”) and began recognizing royalty revenue in fiscal year 2009 for Bristol’s net sales in the United States of Orencia^® which is used in the treatment of rheumatoid arthritis. The royalty agreement with Bristol provided that the Company would receive such royalty payments on sales of Orencia^® by Bristol through December 31, 2013. These royalty payments have ceased. Pursuant to the settlement with Bristol (“Bristol Settlement”), the Company recognized royalty revenue of approximately $0 and $3,846,000 for the three months ended March 31, 2014 and 2013, respectively. Revenue earned from Bristol royalties was recorded in the periods when it was earned based on royalty reports sent by Bristol to the Company. The Company has no continuing obligations to Bristol as a result of this settlement.

Pursuant to the Bristol Settlement, Repligen remitted to the University of Michigan 15% of all royalty revenue received from Bristol. Royalty expense for the three months ended March 31, 2014 and March 31, 2013 was approximately $0 and $577,000, respectively. This operating expense has been included in the Company’s Statements of Operations under the line item “Cost of royalty revenue.”

Research and Development Agreements

For the three months ended March 31, 2014 and March 31, 2013, the Company recognized approximately $0 and $621,000, respectively, of revenue from a sponsored research and development project under an agreement with the National Institutes of Health / Scripps Research Institute.

Research revenue is recognized when the expense has been incurred and services have been performed. Determination of which incurred costs qualify for reimbursement under the terms of the Company’s contractual agreements and the timing of when such costs were incurred involves the judgment of management. The Company’s calculations are based on the agreed-upon terms as stated in the arrangements. However, should the estimated calculations change or be challenged by other parties to the agreements, research revenue may be adjusted in subsequent periods. The calculations have not historically changed or been challenged, and the Company does not anticipate any significant subsequent change in its revenue related to sponsored research and development projects.

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Basic and Diluted Weighted Average Shares Outstanding (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Weighted Average Number of Shares Outstanding [Line Items]
Weighted average common shares	31,962,843	31,240,606
Dilutive common stock options	868,176	614,822
Weighted average common shares, assuming dilution	32,831,019	31,855,428

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Contractual Maturities of Money Market Funds and Marketable Securities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Due in 1 year or less	$ 21,546,789
Due in 1 to 2 years	10,912,224
Amortized Cost	32,459,013	34,017,451
Due in 1 year or less	21,551,398
Due in 1 to 2 years	10,904,518
Fair Value	$ 32,455,916	$ 34,012,152

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Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 49,209,621	$ 39,829,653
Marketable securities	21,551,398	21,793,550
Accounts receivable, less reserve for doubtful accounts of $10,000	5,036,909	4,946,132
Royalties and other receivables		6,730,818
Inventories	11,441,317	11,798,638
Deferred tax asset, net	1,984	1,984
Prepaid expenses and other current assets	1,456,208	1,249,824
Total current assets	88,697,437	86,350,599
Property, plant and equipment, at cost:
Leasehold improvements	9,207,709	8,973,615
Equipment	13,939,322	13,684,954
Furniture and fixtures	2,175,604	2,116,017
Construction in progress	35,168	21,647
Total property, plant and equipment, at cost	25,357,803	24,796,233
Less: Accumulated depreciation	(12,911,214)	(12,287,010)
Property, plant and equipment, net	12,446,589	12,509,223
Long-term deferred tax asset, net	176,742	184,848
Long-term marketable securities	10,904,518	12,218,602
Intangible assets, net	5,915,105	6,187,632
Goodwill	994,000	994,000
Restricted cash	200,000	200,000
Total assets	119,334,391	118,644,904
Current liabilities:
Accounts payable	1,483,447	1,721,459
Accrued liabilities	5,638,935	9,579,712
Total current liabilities	7,122,382	11,301,171
Other long-term liabilities	3,360,477	3,457,631
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.01 par value, 5,000,000 shares authorized, no shares issued or outstanding
Common stock, $.01 par value, 40,000,000 shares authorized, 32,040,683 shares at March 31, 2014 and 31,925,741 shares at December 31, 2013 issued and outstanding	320,407	319,257
Additional paid-in capital	191,454,083	190,625,937
Accumulated other comprehensive income	1,857,361	1,998,330
Accumulated deficit	(84,780,319)	(89,057,422)
Total stockholders' equity	108,851,532	103,886,102
Total liabilities and stockholders' equity	$ 119,334,391	$ 118,644,904

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Schedule of Inventories (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Inventory [Line Items]
Raw materials	$ 4,224,034	$ 4,557,870
Work-in-process	3,032,739	4,285,648
Finished products	4,184,544	2,955,120
Total	$ 11,441,317	$ 11,798,638

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Basis of Presentation

3 Months Ended

Mar. 31, 2014

Basis of Presentation

1. Basis of Presentation

The consolidated financial statements included herein have been prepared by Repligen Corporation (the “Company,” “Repligen” or “we”) in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”), for Quarterly Reports on Form 10-Q and Article 10 of Regulation S-X and do not include all of the information and footnote disclosures required by U.S. GAAP. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.

In the opinion of management, the accompanying unaudited consolidated financial statements include all adjustments, consisting of only normal, recurring adjustments necessary for a fair presentation of the financial position, results of operations and cash flows. The results of operations for the interim periods presented are not necessarily indicative of results to be expected for the entire year.

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

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Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 307,425	$ 250,071
Cost of product revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	26,562	11,664
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	31,603	7,640
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 249,260	$ 230,767

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Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

Stock-Based Compensation Expense

The following table presents stock-based compensation expense included in the Company’s consolidated statements of comprehensive income:

	Three Months Ended March 31,
	2014		2013
Cost of product revenue	$	26,562	$	11,664
Research and development		31,603		7,640
Selling, general and administrative		249,260		230,767
Total	$	307,425	$	250,071

Summary of Option Activity

Information regarding option activity for the three months ended March 31, 2014 under the Plans is summarized below:

	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2014		1,610,988		$	5.07
Granted		181,431			11.14
Exercised		(114,942	)		4.54
Forfeited/Cancelled		(2,400	)		5.12
Options outstanding at March 31, 2014		1,675,077		$	5.78		6.98	$	12,256,703
Options exercisable at March 31, 2014		834,186		$	4.29		5.13	$	7,146,702
Vested and expected to vest at March 31, 2014 (1)		1,577,600		$	5.67		6.88	$	11,700,596

(1) This represents the number of vested options as of March 31, 2014 plus the number of unvested options expected to vest as of March 31, 2014 based on the unvested outstanding options at March 31, 2014 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

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Summary of Information Regarding Option Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Options Outstanding
Options outstanding at January 1, 2014	1,610,988		2,231,590
Granted	181,431
Exercised	(114,942)
Forfeited/Cancelled	(2,400)
Options outstanding at March 31, 2014	1,675,077		2,231,590
Options exercisable at March 31, 2014	834,186
Vested and expected to vest at March 31, 2014	1,577,600	[1]
Weighted-Average Exercise Price Per Share
Options outstanding at January 1, 2014	$ 5.07		$ 4.40
Granted	$ 11.14
Exercised	$ 4.54
Forfeited/Cancelled	$ 5.12
Options outstanding at March 31, 2014	$ 5.78		$ 4.40
Options exercisable at March 31, 2014	$ 4.29
Vested and expected to vest at March 31, 2014	$ 5.67	[1]
Weighted-Average Remaining Contractual Term (in years)
Options outstanding at March 31, 2014	6 years 11 months 23 days
Options exercisable at March 31, 2014	5 years 1 month 17 days
Vested and expected to vest at March 31, 2014	6 years 10 months 17 days	[1]
Aggregate Intrinsic Value
Options outstanding at March 31, 2014	$ 12,256,703
Options exercisable at March 31, 2014	7,146,702
Vested and expected to vest at March 31, 2014	$ 11,700,596	[1]

[1] This represents the number of vested options as of March 31, 2014 plus the number of unvested options expected to vest as of March 31, 2014 based on the unvested outstanding options at March 31, 2014 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

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Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2014

Assets Measured at Fair Value on Recurring Basis

The following fair value hierarchy table presents information about each major category of the Company’s assets measured at fair value on a recurring basis as of March 31, 2014:

	Fair value measurement at reporting date using:
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Assets:
Money market funds	$	11,953,743	$	—	$	—	$	11,953,743
U.S. Government and agency securities		10,204,720		8,237,841		—		18,442,561
Corporate and other debt securities		—		14,013,355		—		14,013,355
Total	$	22,158,463	$	22,251,196	$	—	$	44,409,659

Roll Forward of Fair Value of Contingent Consideration

The following table provides a roll forward of the fair value of the contingent consideration:

Balance at December 31, 2013	$	1,648,928
Additions		—
Payments		(80,000	)
Changes in fair value		97,777
Balance at March 31, 2014	$	1,666,705

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Goodwill and Intangible Assets

3 Months Ended

Mar. 31, 2014

Goodwill and Intangible Assets

2. Goodwill and Intangible Assets

Goodwill

Goodwill is not amortized and is reviewed for impairment at least annually. There was no evidence of impairment to goodwill at March 31, 2014. There were no goodwill impairment charges during the three-month period ended March 31, 2014.

Intangible Assets

Intangible assets are amortized over their useful lives using the estimated economic benefit method, as applicable, and the amortization expense is recorded within selling, general and administrative expense in the Company’s statements of comprehensive income (loss). Intangible assets and their related useful lives are reviewed at least annually to determine if any adverse conditions exist that would indicate the carrying value of these assets may not be recoverable. More frequent impairment assessments are conducted if certain conditions exist, including a change in the competitive landscape, any internal decisions to pursue new or different technology strategies, a loss of a significant customer, or a significant change in the marketplace, including changes in the prices paid for our products or changes in the size of the market for our products. An impairment results if the carrying value of the asset exceeds the estimated fair value of the asset. If the estimate of an intangible asset’s remaining useful life is changed, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. The Company continues to believe that its intangible assets are recoverable at March 31, 2014.

Intangible assets consisted of the following at March 31, 2014:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,453,006	$	(581,084	)		8
Patents		240,000		(125,000	)		8
Customer relationships		6,874,961		(1,946,778	)		8
Total intangible assets	$	8,567,967	$	(2,652,862	)		8

Intangible assets consisted of the following at December 31, 2013:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,455,382	$	(537,589	)		8
Patents		240,000		(117,500	)		8
Customer relationships		6,897,052		(1,749,713	)		8
Total intangible assets	$	8,592,434	$	(2,404,802	)		8

Amortization expense for amortized intangible assets was approximately $248,000 for the three months ended March 31, 2014. The Company expects to record amortization expense of approximately $1,000,000 in each of the next five years related to these intangible assets.

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Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Accounts receivable, reserve for doubtful accounts	$ 10,000	$ 10,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	32,040,683	31,925,741
Common stock, shares outstanding	32,040,683	31,925,741

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Income Taxes

3 Months Ended

Mar. 31, 2014

Income Taxes

12. Income Taxes

For the three months ended March 31, 2014, the Company had income before taxes of approximately $5,398,000 and recorded a tax provision of approximately $1,121,000 for an effective tax rate of approximately 20.8%. This is based on an expected effective tax rate of 20.9% for the year ending December 31, 2014. For the three months ended March 31, 2013, the Company had income before taxes of approximately $3,622,000 and recorded a tax provision of $1,284,000 for an effective tax rate of approximately 35.45%. This was based on an expected effective tax rate of 28.21% for the year ending December 31, 2013 plus approximately $298,000 of discrete items recognized in the quarter ended March 31, 2013. The effective income tax rate is based upon the estimated income for the year and the composition of the income in different jurisdictions. The effective tax rate differs from the U.S. statutory tax rate primarily due to the lower statutory tax rate in Sweden.

The Company has net operating loss carryforwards of approximately $37,633,000 and business tax credits carryforwards of approximately $1,520,000 available to reduce future federal income taxes, if any. The net operating loss and business tax credits carryforwards will continue to expire at various dates through December 2031. Net operating loss carryforwards and available tax credits are subject to review and possible adjustment by the Internal Revenue Service and may be limited in the event of certain changes in the ownership interest of significant stockholders.

In the fourth quarter of 2012, we entered into a cumulative pre-tax income position and concluded that it was more likely than not that we would generate sufficient taxable income in 2013 based on our 2013 projections to realize the tax benefit of a portion of our deferred tax assets. We accordingly recorded a tax benefit in the fourth quarter of 2012 that included the reversal of $3,021,000 of the valuation allowance on our deferred tax assets. At December 31, 2013, as a result of the fact that we no longer receive royalty payments on Bristol’s sales of Orencia, we concluded that realization of deferred tax assets beyond December 31, 2013 was not more likely than not and we therefore maintained a valuation allowance against the majority of our remaining deferred tax assets. As of March 31, 2014, we continue to maintain a valuation allowance against the majority of our remaining deferred tax assets as we concluded that realization of deferred tax assets for the year ended December 31, 2014 and beyond was not more likely than not.

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Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 14, 2014
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Trading Symbol	RGEN
Entity Registrant Name	REPLIGEN CORP
Entity Central Index Key	0000730272
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		32,039,883

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Segment Reporting

3 Months Ended

Mar. 31, 2014

Segment Reporting

13. Segment Reporting

The Company views its operations, makes decisions regarding how to allocate resources and manages its business as one operating segment. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s principal operating segment.

The following table represents the Company’s total revenue by geographic area (based on the location of the customer):

	Three months ended March 31,
	2014			2013
United States		49	%		47	%
Sweden		32	%		39	%
United Kingdom		18	%		12	%
Other		1	%		2	%
		100	%		100	%

Revenue from significant customers as a percentage of the Company’s total revenue is as follows:

	Three months ended March 31,
	2014			2013
Upfront payment from sale of intellectual property to BioMarin		12	%		—
Orencia® Royalties from Bristol		—			24	%
Bioprocessing Customer A		40	%		38	%
Bioprocessing Customer B		22	%		12	%
Bioprocessing Customer C		14	%		15	%

Significant accounts receivable balances as a percentage of the Company’s total trade accounts receivable and royalties and other receivables balances are as follows:

	March 31, 2014			December 31, 2013
Orencia® Royalties from Bristol		—			42	%
Bioprocessing Customer A		58	%		17	%
Bioprocessing Customer B		22	%		8	%
Tenant improvement allowance due from landlord		—			15	%

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Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenue:
Product revenue	$ 14,334,687	$ 11,934,269
Royalty and other revenue	1,991,166	4,521,724
Total revenue	16,325,853	16,455,993
Operating expenses:
Cost of product revenue	6,335,064	6,896,608
Cost of royalty revenue		576,857
Research and development	1,200,990	2,183,404
Selling, general and administrative	3,383,610	3,308,099
Contingent consideration - fair value adjustments	98,320	(53,974)
Total operating expenses	11,017,984	12,910,994
Income from operations	5,307,869	3,544,999
Investment income	101,816	61,519
Interest expense	(14,085)	(13,531)
Other income	2,505	29,081
Income before income taxes	5,398,105	3,622,068
Income tax provision	1,121,002	1,283,832
Net income	4,277,103	2,338,236
Earnings per share:
Basic	$ 0.13	$ 0.07
Diluted	$ 0.13	$ 0.07
Weighted average shares outstanding:
Basic	31,962,843	31,240,606
Diluted	32,831,019	31,855,428
Other comprehensive income:
Unrealized gain (loss) on investments	2,184	(1,983)
Foreign currency translation loss	(143,153)	(256,608)
Comprehensive income	$ 4,136,134	$ 2,079,645

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Cash, Cash Equivalents and Marketable Securities

3 Months Ended

Mar. 31, 2014

Cash, Cash Equivalents and Marketable Securities

7. Cash, Cash Equivalents and Marketable Securities

At March 31, 2014 and December 31, 2013, the Company’s investments included money market funds as well as short-term and long-term marketable securities. These marketable securities are classified as available-for-sale. Marketable securities are investments with original maturities of greater than 90 days. Long-term marketable securities are securities with maturities of greater than one year. The average remaining contractual maturity of marketable securities at March 31, 2014 is approximately 9.53 months.

Management reviewed the Company’s investments as of March 31, 2014 and December 31, 2013 and concluded that there are no securities with other than temporary impairments in the investment portfolio. The Company does not intend to sell any investments in an unrealized loss position and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases.

Investments in money market funds and marketable securities consisted of the following at March 31, 2014:

	March 31, 2014
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	9,529,909	$	2,415	$	(120	)	$	9,532,204
Corporate and other debt securities		12,016,880		4,043		(1,729	)		12,019,194
		21,546,789		6,458		(1,849	)		21,551,398
Long-term marketable securities:
U.S. Government and agency securities		8,918,120		516		(8,279	)		8,910,357
Corporate and other debt securities		1,994,104		1,915		(1,858	)		1,994,161
		10,912,224		2,431		(10,137	)		10,904,518
Total	$	32,459,013	$	8,889	$	(11,986	)	$	32,455,916

At March 31, 2014, the Company’s investments included thirty securities in unrealized loss positions with a total unrealized loss of approximately $12,000 and a total fair market value of approximately $14,141,000. All investments with gross unrealized losses have been in unrealized loss positions for less than 12 months. The unrealized losses were caused primarily by current economic and market conditions. There was no change in the credit risk of the securities. There were no realized gains or losses on the investments for the three months ended March 31, 2014 or the year ended December 31, 2013.

Investments in money market funds and marketable securities consisted of the following at December 31, 2013:

	December 31, 2013
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	8,165,464	$	435	$	(630	)	$	8,165,269
Corporate and other debt securities		13,626,690		3,636		(2,045	)		13,628,281
		21,792,154		4,071		(2,675	)		21,793,550
Long-term marketable securities:
U.S. Government and agency securities		11,599,415		466		(7,034	)		11,592,847
Corporate and other debt securities		625,882		100		(227	)		625,755
		12,225,297		566		(7,261	)		12,218,602
Total	$	34,017,451	$	4,637	$	(9,936	)	$	34,012,152

The contractual maturities of money market funds and marketable securities at March 31, 2014 were as follows:

	Amortized Cost		Fair Value
Due in 1 year or less	$	21,546,789	$	21,551,398
Due in 1 to 2 years		10,912,224		10,904,518
	$	32,459,013	$	32,455,916

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Stock-Based Compensation

3 Months Ended

Mar. 31, 2014

Stock-Based Compensation

6. Stock-Based Compensation

For the three months ended March 31, 2014 and 2013, the Company recorded stock-based compensation expense of $307,425 and $250,071, respectively, for share-based awards granted under the Second Amended and Restated 2001 Repligen Corporation Stock Plan (the “2001 Plan”) and the Repligen Corporation 2012 Stock Option and Incentive Plan (the “2012 Plan,” and collectively with the 2001 Plan and the 1992 Repligen Corporation Stock Option Plan, the “Plans”).

The following table presents stock-based compensation expense included in the Company’s consolidated statements of comprehensive income:

	Three Months Ended March 31,
	2014		2013
Cost of product revenue	$	26,562	$	11,664
Research and development		31,603		7,640
Selling, general and administrative		249,260		230,767
Total	$	307,425	$	250,071

The 2012 Plan allows for the granting of incentive and nonqualified options to purchase shares of common stock, restricted stock and other equity awards. Incentive options granted to employees under the Plans generally vest over a four to five-year period, with 20%-25% vesting on the first anniversary of the date of grant and the remainder vesting in equal yearly installments thereafter. Nonqualified options issued to non-employee directors and consultants under the Plans generally vest over one year. Options granted under the Plans have a maximum term of ten years from the date of grant and generally, the exercise price of the stock options equals the fair market value of the Company’s common stock on the date of grant. At March 31, 2014, options to purchase 1,675,077 shares were outstanding under the Plans. At March 31, 2014, 944,646 shares were available for future grant under the 2012 Plan.

The Company uses the Black-Scholes option pricing model to calculate the fair value of share-based awards on the grant date. The Company measures stock-based compensation cost at the grant date based on the estimated fair value of the award, and recognizes awards with service based vesting as expense over the employee’s requisite service period on a straight-line basis. The Company records the expense for share-based awards subject to performance-based milestone vesting over the remaining service period when management determines that achievement of the milestone is probable. Management evaluates whether the achievement of a performance-based milestone is probable as of the reporting date. The Company has no awards that are subject to market conditions. The Company recognizes stock-based compensation expense for options that are ultimately expected to vest, and accordingly, such compensation expense has been adjusted for estimated forfeitures.

Information regarding option activity for the three months ended March 31, 2014 under the Plans is summarized below:

	Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Options outstanding at January 1, 2014		1,610,988		$	5.07
Granted		181,431			11.14
Exercised		(114,942	)		4.54
Forfeited/Cancelled		(2,400	)		5.12
Options outstanding at March 31, 2014		1,675,077		$	5.78		6.98	$	12,256,703
Options exercisable at March 31, 2014		834,186		$	4.29		5.13	$	7,146,702
Vested and expected to vest at March 31, 2014 (1)		1,577,600		$	5.67		6.88	$	11,700,596

(1) This represents the number of vested options as of March 31, 2014 plus the number of unvested options expected to vest as of March 31, 2014 based on the unvested outstanding options at March 31, 2014 adjusted for estimated forfeiture rates of 8% for awards granted to non-executive level employees and 3% for awards granted to executive level employees.

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value (the difference between the closing price of the common stock on March 31, 2014 of $12.86 and the exercise price of each in-the-money option) that would have been received by the option holders had all option holders exercised their options on March 31, 2014.

The weighted average grant date fair value of options granted during the three months ended March 31, 2014 and 2013 was $10.58 and $3.26, respectively. The total fair value of stock options that vested during the three months ended March 31, 2014 and 2013 was approximately $343,667 and $232,617, respectively.

As of March 31, 2014, there was $3,364,170 of total unrecognized compensation cost related to unvested share-based awards. This cost is expected to be recognized over a weighted average remaining requisite service period of 3.09 years. The Company expects 743,414 unvested options to vest over the next five years.

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Cash, Cash Equivalents and Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2014

Investments in Money Market Funds and Marketable Securities

Investments in money market funds and marketable securities consisted of the following at March 31, 2014:

	March 31, 2014
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	9,529,909	$	2,415	$	(120	)	$	9,532,204
Corporate and other debt securities		12,016,880		4,043		(1,729	)		12,019,194
		21,546,789		6,458		(1,849	)		21,551,398
Long-term marketable securities:
U.S. Government and agency securities		8,918,120		516		(8,279	)		8,910,357
Corporate and other debt securities		1,994,104		1,915		(1,858	)		1,994,161
		10,912,224		2,431		(10,137	)		10,904,518
Total	$	32,459,013	$	8,889	$	(11,986	)	$	32,455,916

Investments in money market funds and marketable securities consisted of the following at December 31, 2013:

	December 31, 2013
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Marketable securities:
U.S. Government and agency securities	$	8,165,464	$	435	$	(630	)	$	8,165,269
Corporate and other debt securities		13,626,690		3,636		(2,045	)		13,628,281
		21,792,154		4,071		(2,675	)		21,793,550
Long-term marketable securities:
U.S. Government and agency securities		11,599,415		466		(7,034	)		11,592,847
Corporate and other debt securities		625,882		100		(227	)		625,755
		12,225,297		566		(7,261	)		12,218,602
Total	$	34,017,451	$	4,637	$	(9,936	)	$	34,012,152

Contractual Maturities of Money Market Funds and Marketable Securities

The contractual maturities of money market funds and marketable securities at March 31, 2014 were as follows:

	Amortized Cost		Fair Value
Due in 1 year or less	$	21,546,789	$	21,551,398
Due in 1 to 2 years		10,912,224		10,904,518
	$	32,459,013	$	32,455,916

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Goodwill and Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2014

Intangible Assets

Intangible assets consisted of the following at March 31, 2014:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,453,006	$	(581,084	)		8
Patents		240,000		(125,000	)		8
Customer relationships		6,874,961		(1,946,778	)		8
Total intangible assets	$	8,567,967	$	(2,652,862	)		8

Intangible assets consisted of the following at December 31, 2013:

	Gross Carrying Amount		Accumulated Amortization			Weighted Average Useful Life (in years)
Technology – developed	$	1,455,382	$	(537,589	)		8
Patents		240,000		(117,500	)		8
Customer relationships		6,897,052		(1,749,713	)		8
Total intangible assets	$	8,592,434	$	(2,404,802	)		8

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Accrued Liabilities

3 Months Ended

Mar. 31, 2014

Accrued Liabilities

10. Accrued Liabilities

The Company estimates accrued liabilities by identifying services performed on the Company’s behalf, estimating the level of service performed and determining the associated cost incurred for such service as of each balance sheet date. For example, the Company would accrue for professional and consulting fees incurred with law firms, audit and accounting service providers and other third party consultants. These expenses are determined by either requesting those service providers to estimate unbilled services at each reporting date for services incurred or tracking costs incurred by service providers under fixed fee arrangements.

The Company has processes in place to estimate the appropriate amounts to record for accrued liabilities, which principally involve the applicable personnel reviewing the services provided. In the event that the Company does not identify certain costs that have begun to be incurred or the Company under or over-estimates the level of services performed or the costs of such services, the reported expenses for that period may be too low or too high. The date on which certain services commence, the level of services performed on or before a given date, and the cost of such services often require the exercise of judgment. The Company makes these judgments based upon the facts and circumstances known at the date of the financial statements.

Accrued liabilities consist of the following:

	March 31, 2014		December 31, 2013
Employee compensation	$	2,228,965	$	3,166,086
Taxes		655,703		2,324,711
Royalty and license fees		560,501		1,897,473
Contingent consideration (current portion)		1,313,145		1,195,248
Unearned revenue		—		3,341
Professional fees		402,820		385,478
VAT liabilities		—		7,591
Other accrued expenses		477,801		599,784
Total		5,638,935		9,579,712

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Fair Value Measurement

3 Months Ended

Mar. 31, 2014

Fair Value Measurement

8. Fair Value Measurement

In determining the fair value of its assets and liabilities, the Company uses various valuation approaches. The Company employs a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. The fair value hierarchy is broken down into three levels based on the source of inputs as follows:

Level 1	–	Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access
Level 2	–	Valuations based on quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active and models for which all significant inputs are observable, either directly or indirectly
Level 3	–	Valuations based on inputs that are unobservable and significant to the overall fair value measurement

The availability of observable inputs can vary among the various types of financial assets and liabilities. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for financial statement disclosure purposes, the level in the fair value hierarchy within which the fair value measurement is categorized is based on the lowest level input that is significant to the overall fair value measurement.

The Company’s fixed income investments are comprised of obligations of U.S. government agencies and corporate marketable securities. These investments have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third party pricing services or other market observable data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. These observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates and other industry and economic events. At least annually, the Company validates the prices provided by third party pricing services by reviewing their pricing methods and matrices, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming that the relevant markets are active. The Company did not adjust or override any fair value measurements provided by the pricing services as of March 31, 2014.

The following fair value hierarchy table presents information about each major category of the Company’s assets measured at fair value on a recurring basis as of March 31, 2014:

	Fair value measurement at reporting date using:
	Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Assets:
Money market funds	$	11,953,743	$	—	$	—	$	11,953,743
U.S. Government and agency securities		10,204,720		8,237,841		—		18,442,561
Corporate and other debt securities		—		14,013,355		—		14,013,355
Total	$	22,158,463	$	22,251,196	$	—	$	44,409,659

The Company has no other assets or liabilities for which fair value measurement is either required or has been elected to be applied, other than the liabilities for contingent consideration recorded in connection with the Novozymes Acquisition and the acquisition of the assets of BioFlash Partners, LLC (“BioFlash”). The contingent consideration related to Novozymes is valued based upon an updated agreement with Novozymes Biopharma DK A/S, a company organized under the laws of Denmark (“Novozymes Denmark”). The contingent consideration related to BioFlash is valued using management’s estimates of royalties to be paid to the former shareholders of BioFlash based on sales of the acquired assets. These valuations are Level 3 valuations as the primary inputs are unobservable. Changes in the fair value of contingent consideration in the three-month period ended March 31, 2014 are primarily attributable to a $80,000 minimum royalty payment made to BioFlash, which was previously accrued, and a fair value adjustment of approximately $92,000 due to our agreement with Novozymes Denmark. The following table provides a roll forward of the fair value of the contingent consideration:

Balance at December 31, 2013	$	1,648,928
Additions		—
Payments		(80,000	)
Changes in fair value		97,777
Balance at March 31, 2014	$	1,666,705

There were no remeasurements to fair value during the three months ended March 31, 2014 of financial assets and liabilities that are not measured at fair value on a recurring basis.

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Inventories

3 Months Ended

Mar. 31, 2014

Inventories

9. Inventories

Inventories relate to the Company’s bioprocessing business. The Company values inventory at cost or, if lower, fair market value, using the first-in, first-out method. The Company reviews its inventories at least quarterly and records a provision for excess and obsolete inventory based on its estimates of expected sales volume, production capacity and expiration dates of raw materials, work-in process and finished products. Expected sales volumes are determined based on supply forecasts provided by key customers for the next three to 12 months. The Company writes down inventory that has become obsolete, inventory that has a cost basis in excess of its expected net realizable value, and inventory in excess of expected requirements to cost of product revenue. Manufacturing of bioprocessing finished goods is done to order and tested for quality specifications prior to shipment. Reserves for excess and obsolete inventory were approximately $182,000 at March 31, 2014 and $183,000 at December 31, 2013.

A change in the estimated timing or amount of demand for the Company’s products could result in additional provisions for excess inventory quantities on hand. Any significant unanticipated changes in demand or unexpected quality failures could have a significant impact on the value of inventory and reported operating results. During all periods presented in the accompanying financial statements, there have been no material adjustments related to a revised estimate of inventory valuations.

Work-in-process and finished products inventories consist of material, labor, outside processing costs and manufacturing overhead. Inventories consist of the following:

	March 31, 2014		December 31, 2013
Raw materials	$	4,224,034	$	4,557,870
Work-in-process		3,032,739		4,285,648
Finished products		4,184,544		2,955,120
Total	$	11,441,317	$	11,798,638

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Commitments and Contingencies

3 Months Ended

Mar. 31, 2014

Commitments and Contingencies

11. Commitments and Contingencies

In March 2014, the Company entered into an amendment of its existing lease to expand the rented space from 55,694 to 75,594 square feet at 41 Seyon Street, Waltham, Massachusetts. Pursuant to the terms of the amended lease, Repligen will lease an additional 19,900 square feet (the “Expansion Space”) for a period of eight years and one month, commencing on August 1, 2014 or the date upon which the landlord’s improvements to the Expansion Space have been completed, whichever is later. The Expansion Space shall become a part of Repligen’s corporate headquarters.

The amended lease provides for additional rent expense of approximately $361,000 on an annualized basis. The amended lease also requires an increased security deposit from $200,000 to $450,000 and continues to require the Company to pay a proportionate share of certain of the landlord’s annual operating costs and real estate taxes. Future minimum rental commitments under the amended lease as of March 31, 2014 are approximately $908,000 and $1,371,000 for the remainder of the year ending December 31, 2014, and the years ending December 31, 2015, 2016, 2017 and 2018, respectively.

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Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended				12 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 2012 Plan	Dec. 31, 2012 Employee Stock Option Minimum	Dec. 31, 2012 Employee Stock Option Maximum	Dec. 31, 2012 Non-Employee Directors and Consultants	Mar. 31, 2014 Unvested Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 307,425	$ 250,071
Incentive options, vesting period					4 years	5 years	1 year	5 years
Incentive options, vesting on the first anniversary of the date of grant					20.00%	25.00%
Incentive options, term						10 years
Stock options outstanding	1,675,077	2,231,590	1,610,988
Number of shares available for future grant				944,646
Closing price of common stock	$ 12.86
Weighted average grant date fair value of share-based awards granted	$ 10.58	$ 3.26
Total fair value of stock options vested	343,667	232,617
Total unrecognized compensation cost	$ 3,364,170
Unrecognized compensation cost, weighted average remaining requisite service period	3 years 1 month 2 days
Number of unvested options	743,414

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Percentage of Revenue from Significant Customers (Detail) (Sales)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
BioMarin Pharmaceutical, Inc.
Revenue, Major Customer [Line Items]
Concentration risk percentage	12.00%
Orencia Royalties from Bristol
Revenue, Major Customer [Line Items]
Concentration risk percentage		24.00%
Bioprocessing Customer A
Revenue, Major Customer [Line Items]
Concentration risk percentage	40.00%	38.00%
Bioprocessing Customer B
Revenue, Major Customer [Line Items]
Concentration risk percentage	22.00%	12.00%
Bioprocessing Customer C
Revenue, Major Customer [Line Items]
Concentration risk percentage	14.00%	15.00%

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Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2014

Basic and Diluted Weighted Average Shares Outstanding

Basic and diluted weighted average shares outstanding were as follows:

	Three Months Ended March 31,
	2014		2013
Weighted average common shares		31,962,843		31,240,606
Dilutive common stock options		868,176		614,822
Weighted average common shares, assuming dilution		32,831,019		31,855,428

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Accrued Liabilities (Tables)

3 Months Ended

Mar. 31, 2014

Schedule of Accrued Liabilities

Accrued liabilities consist of the following:

	March 31, 2014		December 31, 2013
Employee compensation	$	2,228,965	$	3,166,086
Taxes		655,703		2,324,711
Royalty and license fees		560,501		1,897,473
Contingent consideration (current portion)		1,313,145		1,195,248
Unearned revenue		—		3,341
Professional fees		402,820		385,478
VAT liabilities		—		7,591
Other accrued expenses		477,801		599,784
Total		5,638,935		9,579,712

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Segment Reporting - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014 Segment
Segment Reporting Information [Line Items]
Number of operating segment	1

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Major Category of Assets Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $)	Mar. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	$ 44,409,659
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	11,953,743
U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	18,442,561
Corporate and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	14,013,355
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	22,158,463
Quoted prices in active markets for identical assets (Level 1) | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	11,953,743
Quoted prices in active markets for identical assets (Level 1) | U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	10,204,720
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	22,251,196
Significant other observable inputs (Level 2) | U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	8,237,841
Significant other observable inputs (Level 2) | Corporate and other debt securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Assets	$ 14,013,355

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Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income:	$ 4,277,103	$ 2,338,236
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	892,407	818,920
Stock-based compensation expense	307,425	250,071
Deferred tax expense	7,566	(112,403)
Loss (gain) on revaluation of contingent consideration	98,320	(53,974)
Changes in assets and liabilities:
Accounts receivable	(94,064)	(2,772,175)
Royalties and other receivables	6,730,818	5,284,800
Inventories	331,087	872,260
Prepaid expenses and other current assets	(209,701)	(51,472)
Accounts payable	(236,176)	(548,648)
Accrued liabilities	(3,999,779)	(1,301,152)
Long-term liabilities	(106,216)	(1,129,760)
Net cash provided by operating activities	7,998,790	3,594,703
Cash flows from investing activities:
Purchases of marketable securities	(8,970,763)	(10,538,701)
Redemptions of marketable securities	10,529,183	5,811,555
Purchases of property, plant and equipment	(596,788)	(322,099)
Net cash provided by (used in) investing activities	961,632	(5,049,245)
Cash flows from financing activities:
Exercise of stock options	497,709	956,721
Net cash provided by financing activities	497,709	956,721
Effect of exchange rate changes on cash and cash equivalents	(78,163)	(141,985)
Net increase (decrease) in cash and cash equivalents	9,379,968	(639,806)
Cash and cash equivalents, beginning of period	39,829,653	29,209,821
Cash and cash equivalents, end of period	49,209,621	28,570,015
Supplemental disclosure of non-cash investing activities:
Income taxes paid	$ 466,000	$ 659,000

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Earnings Per Share

3 Months Ended

Mar. 31, 2014

Earnings Per Share

5. Earnings Per Share

The Company reports earnings per share in accordance with Accounting Standards Codification Topic 260, “Earnings Per Share,” which establishes standards for computing and presenting earnings per share. Basic earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of common shares outstanding during the period. Diluted earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of common shares and dilutive common share equivalents then outstanding. Potential common share equivalents consist of restricted stock awards and the incremental common shares issuable upon the exercise of stock options and warrants. Under the treasury stock method, unexercised “in-the-money” stock options and warrants are assumed to be exercised at the beginning of the period or at issuance, if later. The assumed proceeds are then used to purchase common shares at the average market price during the period. Share-based payment awards that entitle their holders to receive non-forfeitable dividends before vesting are considered participating securities and are considered in the calculation of basic and diluted earnings per share. Performance based option awards have been excluded from this calculation as they would not be issuable as of March 31, 2014 if that were the end of the contingency period.

Basic and diluted weighted average shares outstanding were as follows:

	Three Months Ended March 31,
	2014		2013
Weighted average common shares		31,962,843		31,240,606
Dilutive common stock options		868,176		614,822
Weighted average common shares, assuming dilution		32,831,019		31,855,428

At March 31, 2014, there were outstanding options to purchase 1,675,077 shares of the Company’s common stock at a weighted average exercise price of $5.78 per share. For the three-month period ended March 31, 2014, 207,431 options to purchase shares of the Company’s common stock were excluded from the calculation of diluted earnings per share because the exercise prices of the stock options were greater than or equal to the average price of the common shares, and were therefore anti-dilutive.

At March 31, 2013, there were outstanding options to purchase 2,231,590 shares of the Company’s common stock at a weighted average exercise price of $4.40 per share. For the three-month period ended March 31, 2013, 516,500 options to purchase shares of the Company’s common stock were excluded from the calculation of diluted earnings per share because the exercise prices of the stock options were greater than or equal to the average price of the common shares, and were therefore anti-dilutive.

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Segment Reporting (Tables)

3 Months Ended

Mar. 31, 2014

Percentage of Revenue from Significant Customers

Revenue from significant customers as a percentage of the Company’s total revenue is as follows:

	Three months ended March 31,
	2014			2013
Upfront payment from sale of intellectual property to BioMarin		12	%		—
Orencia® Royalties from Bristol		—			24	%
Bioprocessing Customer A		40	%		38	%
Bioprocessing Customer B		22	%		12	%
Bioprocessing Customer C		14	%		15	%

Total Revenue

Percentage by Geographic Area or Significant Customers

The following table represents the Company’s total revenue by geographic area (based on the location of the customer):

	Three months ended March 31,
	2014			2013
United States		49	%		47	%
Sweden		32	%		39	%
United Kingdom		18	%		12	%
Other		1	%		2	%
		100	%		100	%

Accounts Receivable

Percentage by Geographic Area or Significant Customers

Significant accounts receivable balances as a percentage of the Company’s total trade accounts receivable and royalties and other receivables balances are as follows:

	March 31, 2014			December 31, 2013
Orencia® Royalties from Bristol		—			42	%
Bioprocessing Customer A		58	%		17	%
Bioprocessing Customer B		22	%		8	%
Tenant improvement allowance due from landlord		—			15	%

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Cash Cash Equivalents and Marketable Securities - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014 Investment	Dec. 31, 2013
Cash, cash equivalents and marketable securities [Line Items]
Long-term marketable securities, minimum original maturity term	1 year
Marketable securities, average remaining contractual maturity period	9 years 6 months 11 days
Number of debt securities in unrealized loss positions	30
Debt securities in unrealized loss positions, total unrealized loss	$ 11,986	$ 9,936
Debt securities in unrealized loss positions, total fair market value	14,141,000
Credit risk	0
Gain (loss) on investments	0	0
Debt Securities
Cash, cash equivalents and marketable securities [Line Items]
Debt securities in unrealized loss positions, total unrealized loss	$ 12,000
Minimum
Cash, cash equivalents and marketable securities [Line Items]
Marketable securities, minimum original maturity term	90 days

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Accumulated Other Comprehensive Income (Tables)

3 Months Ended

Mar. 31, 2014

Changes in Accumulated Other Comprehensive Income

The following table summarizes the changes in accumulated other comprehensive income by component:

(In thousands)	Unrealized gain (loss) on investments			Foreign currency translation gain (loss)			Total
Balance at December 31, 2013	$	(5,281	)	$	2,003,611		$	1,998,330
Other comprehensive income before reclassifications		2,184			(143,153	)		(140,969	)
Amounts reclassified from accumulated other comprehensive income		—			—			—
Net current period other comprehensive income		2,184			(143,153	)		(140,969	)
Balance at March 31, 2014	$	(3,097	)	$	1,860,458		$	1,857,361