Stock-based compensation and warrants

9 Months Ended

Sep. 30, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based compensation and warrants

8. Stock-based compensation and warrants

In 2013, the Company’s board of directors and stockholders approved the 2013 Stock Option and Incentive Plan (“2013 Plan”) which allows for the granting of incentive stock options, non-qualified stock options, restricted stock and restricted stock unit awards, as well as other equity awards to the employees, members of the board of directors and consultants of the Company. The 2013 Plan replaced the 2010 Stock Option and Grant Plan. In January 2014, the number of shares of common stock available for issuance under the 2013 Plan was increased by 960 shares as a result of the automatic increase provision of the 2013 Plan. As of September 30, 2014, the total number of shares of common stock available for issuance under the 2013 Plan was 539.

Stock-based compensation expense

Stock-based compensation expense by award type was as follows:

	Three months ended September 30,				Nine months ended September 30,
		2014		2013		2014		2013
Stock options	$	2,303	$	2,495	$	7,115	$	4,757
Restricted stock awards		16		21		47		76
Restricted stock units		567		—		567		—
Employee stock purchase plan		28		—		28		—
	$	2,914	$	2,516	$	7,757	$	4,833

As of September 30, 2014, there was $21,054 and $4,638 of unrecognized stock-based compensation expense, net of estimated forfeitures, related to unvested stock options and restricted stock units, respectively, that is expected to be recognized over a weighted-average period of 2.8 and 1.8 years, respectively.

During the nine months ended September 30, 2014, the Company issued 2 shares of restricted common stock in exchange for consulting services. The shares vested upon issuance and the Company recognized $42 of expense related to the services provided.

During the nine months ended September 30, 2014, 123 options held by former employees were modified to extend the expiration date. The modification was valued using a Black-Scholes option valuation model and the Company accounted for the $643 of incremental value within general and administrative expenses.

Restricted common stock

	Shares			Weighted-average grant date fair value
Unvested balance at December 31, 2013		69		$	0.95
Granted		—			—
Vested		(62	)		0.95
Forfeited		—			—
Unvested balance at September 30, 2014		7		$	0.95

Restricted stock units

	Shares			Weighted-average grant date fair value
Unvested balance at December 31, 2013		—		$	—
Granted		186			30.47
Vested		—			—
Forfeited		(2	)		30.47
Unvested balance at September 30, 2014		184		$	30.47

Stock options

The following table summarizes the stock option activity under the Company’s equity award plans:

	Shares			Weighted-average exercise price per share
Outstanding at December 31, 2013		3,958		$	5.21
Granted		1,023		$	24.78
Exercised		(844	)	$	3.04
Canceled or forfeited		(95	)	$	14.75
Outstanding at September 30, 2014		4,042		$	10.39
Exercisable at September 30, 2014		1,491		$	4.18
Vested and expected to vest at September 30, 2014		3,988		$	10.46

Options exercisable for 844 shares of common stock were exercised during the nine months ended September 30, 2014, resulting in total proceeds to the Company of $2,310. In accordance with the stock option plans, the shares were issued from a pool of shares reserved for issuance under the stock option plans described above.

Employee stock purchase plan

On June 3, 2013, the Company’s board of directors adopted its 2013 Employee Stock Purchase Plan (“2013 ESPP”), which was subsequently approved by its stockholders and became effective upon the closing of the Company’s initial public offering on June 24, 2013. The 2013 ESPP authorizes the initial issuance of up to a total of 238 shares of the Company’s common stock to participating employees. The first offering period under the 2013 ESPP opened on August 1, 2014.

Warrants

As of September 30, 2014 and December 31, 2013, the Company had 338 warrants outstanding to purchase common stock. During the three and nine months ended September 30, 2014, there were no warrants exercised and no cancellations or expirations.