DESCRIPTION OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2013
DESCRIPTION OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of the Company’s management, the unaudited condensed consolidated financial statements have been prepared on the same basis as audited consolidated financial statements and include all adjustments, consisting of only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position, results of operations, comprehensive income (loss) and cash flows. The interim results are not necessarily indicative of the results of operations to be expected for the year ending December 31, 2013 or any other period. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012 filed with the Securities and Exchange Commission (SEC) on February 26, 2013.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Management's Estimates	Use of Management’s Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.
Segment Reporting	Segment Reporting The Company has determined that it operates in a single segment, which is the discovery (research), development and commercialization of human therapeutics. Revenues are generated primarily from the Company’s collaboration agreements with GSK, located in Great Britain, Astellas Pharma Inc. (‘‘Astellas’’) (through January 6, 2012), located in Japan, and Merck (which agreement will terminate in December 2013), located in the United States. All long-lived assets, which were comprised of property and equipment, are maintained in the United States.
Investments in Marketable Securities	Investments in Marketable Securities The Company invests in short-term and long-term marketable securities, primarily corporate notes, government, government agency, and municipal bonds. The Company classifies its marketable securities as available-for-sale securities and reports them at fair value in cash equivalents, short-term investments or marketable securities on the condensed consolidated balance sheets with related unrealized gains and losses included as a component of stockholders’ equity. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, which is included in interest income on the condensed consolidated statements of operations. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in interest income. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. The Company regularly reviews all of its investments for other-than-temporary declines in estimated fair value. The Company’s review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not that the Company will be required to sell the securities before the recovery of their amortized cost basis. When the Company’s management determines that the decline in estimated fair value of an investment is below the amortized cost basis and the decline is other-than-temporary, the Company reduces the carrying value of the security and records a loss for the amount of such decline.
Inventories	Inventories Inventories consist of the Company’s currently marketed product, VIBATIV® (telavancin). The Company values inventory at the lower of cost or net realizable value. The Company determines the cost of inventory using the average-cost method. The Company analyzes its inventory levels quarterly and writes down inventory that is expected to become obsolete, that has a cost basis in excess of its expected net realizable value or for inventory quantities in excess of expected requirements.
Intangible assets	Intangible Assets The Company capitalizes fees paid to licensors related to agreements for approved products or commercialized products. The Company capitalizes these fees as finite-lived intangible assets and amortizes these intangible assets on a straight-line basis over their estimated useful lives once the Company begins recognizing the related royalty revenue. Consistent with the Company’s policy for classification of costs under the research and development collaborative arrangements, the amortization of these intangible assets will be recognized as a reduction of royalty revenue. The Company reviews its intangible assets for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The recoverability of finite-lived intangible assets is measured by comparing the asset’s carrying amount to the expected undiscounted future cash flows that the asset is expected to generate. The determination of recoverability typically requires various estimates and assumptions, including estimating the useful life over which cash flows will occur, their amount, and the asset’s residual value, if any. The Company derives the required cash flow estimates from near-term forecasted product sales and long-term projected sales in the corresponding market.
Revenue Recognition	Revenue Recognition Revenue is recognized when the related costs are incurred and the four basic criteria of revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured. Determination of criteria (3) and (4) are based on management’s judgments regarding the nature of the fee charged for products or services delivered and the collectability of those fees. Where the revenue recognition criteria are not met, the Company defers the recognition of revenue by recording deferred revenue until such time that all criteria are met.
Collaborative Arrangements and Multiple-Element Arrangements	*Collaborative Arrangements and Multiple-Element Arrangements* Revenue from nonrefundable, up-front license or technology access payments under license and collaborative arrangements that are not dependent on any future performance by the Company is recognized when such amounts are earned. If the Company has continuing obligations to perform under the arrangement, such fees are recognized over the estimated period of continuing performance obligation. The Company accounts for multiple element arrangements, such as license and development agreements in which a customer may purchase several deliverables, in accordance with FASB ASC Subtopic 605-25, “Multiple Element Arrangements”. For new or materially amended multiple element arrangements, the Company identifies the deliverables at the inception of the arrangement and each deliverable within a multiple deliverable revenue arrangement is accounted for as a separate unit of accounting if both of the following criteria are met: (1) the delivered item or items have value to the customer on a standalone basis and (2) for an arrangement that includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the Company’s control. The Company allocates revenue to each non-contingent element based on the relative selling price of each element. When applying the relative selling price method, the Company determines the selling price for each deliverable using vendor-specific objective evidence (“VSOE”) of selling price, if it exists, or third-party evidence (“TPE”) of selling price, if it exists. If neither VSOE nor TPE of selling price exist for a deliverable, the Company uses the best estimated selling price for that deliverable. Revenue allocated to each element is then recognized based on when the basic four revenue recognition criteria are met for each element. For multiple-element arrangements entered into prior to January 1, 2011, the Company’s management determined the deliverables under its collaborative arrangements did not meet the criteria to be considered separate accounting units for the purposes of revenue recognition. As a result, the Company recognized revenue from non-refundable, upfront fees and development contingent payments ratably over the term of its performance under the agreements. These upfront or contingent payments received, pending recognition as revenue, are recorded as deferred revenue and are classified as a short-term or long-term liability on the Company’s consolidated balance sheet and amortized over the estimated period of performance. The Company periodically reviews the estimated performance periods of its contracts based on the progress of its programs. Where a portion of non-refundable upfront fees or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as deferred revenue and recognized as revenue or as an accrued liability and recognized as a reduction of research and development expenses ratably over the term of the Company’s estimated performance period under the agreement. The Company’s management determines the estimated performance periods, and they are periodically reviewed based on the progress of the related program. The effect of any change made to an estimated performance period and therefore revenue recognized would occur on a prospective basis in the period that the change was made. Under certain collaborative arrangements, the Company has been reimbursed for a portion of its research and development expenses. These reimbursements have been reflected as a reduction of research and development expense in the Company’s consolidated statements of operations, as the Company does not consider performing research and development services to be a part of its ongoing and central operations. Therefore, the reimbursement of research and developmental services and any amounts allocated to the Company’s research and development services are recorded as a reduction of research and development expense. Amounts deferred under a collaborative arrangement in which the performance obligations are terminated will result in an immediate recognition of any remaining deferred revenue and accrued liability in the period that termination occurred, provided that all performance obligations have been satisfied. The Company accounts for contingent payments in accordance with FASB Subtopic ASC 605-28 “Revenue Recognition—Milestone Method”. The Company recognizes revenue from milestone payments when (i) the milestone event is substantive and its achievability was not reasonably assured at the inception of the agreement and (ii) the Company does not have ongoing performance obligations related to the achievement of the milestone. Milestone payments are considered substantive if all of the following conditions are met: the milestone payment (a) is commensurate with either the Company’s performance to achieve the milestone or the enhancement of the value of the delivered item or items as a result of a specific outcome resulting from the Company’s performance to achieve the milestone, (b) relates solely to past performance, and (c) is reasonable relative to all of the deliverables and payment terms (including other potential milestone consideration) within the arrangement. See Note 3, “Collaborative Arrangements,” for analysis of each milestone event deemed to be substantive or non-substantive. In accordance with FASB Subtopic ASC 808-10, “Collaborative Arrangements,” and pursuant to the Company’s agreement with Astellas, the Company recognized as revenue the net impact of transactions with Astellas related to VIBATIV® inventories including revenue specifically attributable to any sales, and cost of inventories either transferred or expensed as unrealizable.
Product Revenues	*Product Revenues* The Company sells VIBATIV® in the U.S. through a limited number of distributors, and title and risk of loss transfer upon receipt by these distributors. Healthcare providers order VIBATIV® through these distributors. For all product shipped during the three months ended September 30, 2013, the Company is deferring the recognition of revenue until the product is sold through to healthcare providers, the end customers, due to the inherent uncertainties in estimating normal channel inventory at the distributors, and during which period the Company also provided extended payment terms and expanded return rights that allow distributors to return the product up to one year after the product launch. As of September 30, 2013, the Company had deferred revenue of $0.5 million related to VIBATIV® shipments and recorded this amount as a current liability in the condensed consolidated balance sheet. Product sales are recorded net of estimated government-mandated rebates and chargebacks, distribution fees, estimated product returns and other deductions. Reserves are established for these deductions and actual amounts incurred are offset against applicable reserves. The Company reflects these reserves as either a reduction in the related account receivable from the distributor, or as an accrued liability, depending on the nature of the sales deduction. Sales reserves are based on management’s estimates that consider payer mix in target markets, industry benchmarks and experience to date. The Company monitors inventory levels in the distribution channel, as well as sales of VIBATIV® by distributors to healthcare providers, using product-specific data provided by the distributors. Product return allowances are based on amounts owed or to be claimed on related sales. These estimates take into consideration the terms of the Company’s agreements with customers, historical product returns of VIBATIV® experienced by Astellas, rebates or discounts taken, estimated levels of inventory in the distribution channel, the shelf life of the product, and specific known market events, such as competitive pricing and new product introductions. The Company updates its estimates and assumptions each quarter and if actual future results vary from the Company’s estimates, the Company may adjust these estimates, which could have an effect on product sales and earnings in the period of adjustment. Sales Discounts: The Company offers cash discounts to its customers, generally 2% of the sales price, as an incentive for prompt payment. The Company expects its customers to comply with the prompt payment terms to earn the cash discount. The Company accounts for cash discounts by reducing accounts receivable by the full amount and recognizes the discount as a reduction of revenue in the same period the related revenue is recognized. Chargebacks and Government Rebates: For VIBATIV® sales in the U.S., the Company estimates reductions to product sales for qualifying federal and state government programs including discounted pricing offered to PHS as well as government-managed Medicaid programs. The Company’s reserve for PHS is based on actual chargebacks that distributors have claimed for reduced pricing offered to such health care providers. The Company’s accrual for Medicaid is based upon statutorily-defined discounts, estimated payer mix, expected sales to qualified healthcare providers, and the Company’s expectation about future utilization. The Medicaid accrual and government rebates that are invoiced directly to the Company are recorded in other accrued liabilities on the condensed consolidated balance sheet. For qualified programs that can purchase the Company’s products through distributors at a lower contractual government price, the distributors charge back to the Company the difference between their acquisition cost and the lower contractual government price. Distribution Fees and Product Returns: The Company has written contracts with its distributors that include terms for distribution-related fees. The Company records distribution-related fees based on a percentage of the product sales price. The Company offers its distributors a right to return product purchased directly from the Company, which is principally based upon the product’s expiration date. Additionally, the Company has granted more expansive return rights to its distributors for a period of up to twelve months following its product launch of VIBATIV®. The Company will generally accept returns for expired product during the six months prior to and twelve months after the product expiration date on product that had been sold to the Company’s distributors. Product returned is generally not resalable given the nature of the Company’s products and method of administration. The Company has developed estimates for VIBATIV® product returns based upon historical VIBATIV® sales from the Company’s former collaborative partner, Astellas. The Company maintains a policy to record allowances for potentially doubtful accounts for estimated losses resulting from the inability of its customers to make required payments.
Royalties	*Royalties* The Company recognizes royalty revenue on licensee net sales of its products in the period in which the royalties are earned and reported to the Company and collectability is reasonably assured.
Fair Value of Stock-Based Compensation Awards	Fair Value of Stock-Based Compensation Awards The Company uses the Black-Scholes-Merton option pricing model to estimate the fair value of options granted under its equity incentive plans and rights to acquire stock granted under its employee stock purchase plan (ESPP). The Black-Scholes-Merton option valuation model requires the use of assumptions, including the expected term of the award and the expected stock price volatility. The Company uses the “simplified” method as described in Staff Accounting Bulletin No. 107, “Share-Based Payment,” for the expected option term because the usage of its historical option exercise data is limited due to post-IPO exercise restrictions. Beginning April 1, 2011, the Company has used its historical volatility to estimate expected stock price volatility. Prior to April 1, 2011, the Company used peer company price volatility to estimate expected stock price volatility due to the Company’s limited historical common stock price volatility since its initial public offering in 2004. Restricted Stock Units (RSUs) and Restricted Stock Awards (RSAs) are measured based on the fair market values of the underlying stock on the dates of grant. Stock-based compensation expense was calculated based on awards ultimately expected to vest and was reduced for estimated forfeitures at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differed from those estimates. The Company’s estimated annual forfeiture rates for stock options, RSUs and RSAs are based on its historical forfeiture experience. The estimated fair value of stock options, RSUs and RSAs is expensed on a straight-line basis over the expected term of the grant and the estimated fair value of performance-contingent RSUs and RSAs is expensed using an accelerated method over the term of the award once the Company’s management has determined that it is probable that performance milestones will be achieved. Compensation expense for RSUs and RSAs that contain performance conditions is based on the grant date fair value of the award. Compensation expense is recorded over the requisite service period based on management’s best estimate as to whether it is probable that the shares awarded are expected to vest. The Company’s management assesses the probability of the performance milestones being met on a continuous basis. Compensation expense for purchases under the ESPP is recognized based on the fair value of the common stock on the date of offering, less the purchase discount percentage provided for in the plan. The Company has not recognized, and does not expect to recognize in the near future, any tax benefit related to employee stock-based compensation expense as a result of the full valuation allowance on the Company’s deferred tax assets including deferred tax assets related to its net operating loss carryforwards.