6.	Stock-Based Compensation

For the three months ended June 30, 2015 and 2014, the Company recorded stock-based compensation expense of $984,944 and $545,212, respectively, for share-based awards granted under the Second Amended and Restated 2001 Repligen Corporation Stock Plan (the “2001 Plan”) and the Repligen Corporation Amended and Restated 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 Company recorded stock-based compensation expense of $1,686,926 and $852,637 for the six-month periods ended June 30, 2015 and 2014, respectively, for share-based awards granted under the Plans.

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


	Three months ended June 30,				Six months ended June 30,
	2015		2014		2015		2014
Cost of product revenue	$	63,068	$	63,285	$	105,975	$	89,848
Research and development		89,905		80,392		159,177		111,995
Selling, general and administrative		831,971		401,535		1,421,774		650,794

Total	$	984,944	$	545,212	$	1,686,926	$	852,637

The 2012 Plan allows for the granting of incentive and nonqualified options to purchase shares of common stock, restricted stock, restricted stock units and other equity awards. Incentive options and restricted stock units granted to employees under the Plans generally vest over a three to five-year period, with 20%-33% 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 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 June 30, 2015, options to purchase 1,265,486 shares were outstanding under the Plans. At June 30, 2015, 2,490,973 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 performance or market conditions as of June 30, 2015. 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 six months ended June 30, 2015 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, 2015		1,225,117		$	8.31
Granted		224,182			14.31
Exercised		(128,613	)		5.03
Forfeited/Cancelled		(55,200	)		8.96

Options outstanding at June 30, 2015		1,265,486		$	9.68		7.23	$	39,977,638

Options exercisable at June 30, 2015		466,706		$	6.21		5.01	$	16,360,523

Vested and expected to vest at June 30, 2015 ⁽¹⁾		1,184,234		$	9.68		7.19	$	37,410,229

⁽¹⁾

Represents the number of vested options as of June 30, 2015 plus the number of unvested options expected to vest as of June 30, 2015 based on the unvested outstanding options at June 30, 2015 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 June 30, 2015 of $41.27 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 June 30, 2015.

The weighted average grant date fair value of options granted during the six months ended June 30, 2015 and 2014 was $21.83 and $10.85, respectively. The total fair value of stock options that vested during the six months ended June 30, 2015 and 2014 was approximately $1,521,511 and $646,322, respectively.

As of June 30, 2015, there was $7,318,939 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 2.97 years. The Company expects 717,528 unvested options to vest over the next five years.