Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company's Stock Option Activity and Related Information

A summary of the Company’s stock option activity and related information is as follows:

				Options Outstanding
	Shares Available for Grant			Number of Stock Options Outstanding			Weighted- Average Exercise Price		Weighted- Average Remaining ContractualLife (Years)		Aggregate Intrinsic Value
											(In thousands)
Balance at December 31, 2015		3,166,968			6,053,672		$	2.13		7.6	$	20,605
Granted (unaudited)		(34,380	)		34,380			4.90
Exercised (unaudited)		—			(11,563	)		0.74
Cancelled (unaudited)		21,020			(21,020	)		3.38
Balance at March 31, 2016 (unaudited)		3,153,608			6,055,469		$	2.15		7.4	$	14,637
Vested and exercisable at March 31, 2016 (unaudited)					3,459,650		$	1.09		6.3	$	11,302
Vested and expected to vest at March 31, 2016 (unaudited)					5,814,927		$	2.10		7.3	$	14,294

Schedule of Weighted-Average Assumptions Fair Value of Employee Stock Options Estimated Date of Grant Using Black-Scholes Option-Pricing Model

The fair value of employee stock option was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions:  

	Three Months Ended March 31, 2016		Three Months Ended March 31, 2015
	(Unaudited)
Expected term (in years)		6.0		6.0
Expected volatility%		69.8%		52.3%
Risk-free interest rate%		1.5%		1.6%
Expected dividend yield%		0.0%		0.0%

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense recognized in the Company’s condensed consolidated statements of operations is classified as follows (in thousands):

	Three Months Ended March 31, 2016
	2016		2015
	(Unaudited)
Research and development	$	121	$	25
Selling and marketing		24		5
General and administrative		411		44
Total stock-based compensation expense	$	556	$	74