Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 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)		(1,127,703	)		1,127,703			4.25
Exercised (unaudited)		—			(547,211	)		0.70
Cancelled (unaudited)		293,284			(293,284	)		4.39
RSUs granted (unaudited)		(112,578	)		—			—
Balance at September 30, 2016 (unaudited)		2,219,971			6,340,880		$	2.53		7.4	$	13,726
Vested and exercisable at September 30, 2016 (unaudited)					3,574,359		$	1.52		6.4	$	11,091
Vested and expected to vest at September 30, 2016 (unaudited)					6,090,787		$	2.48		7.4	$	13,461

Schedule of Weighted-Average Assumptions Used in Black-Scholes Option-Pricing Model to Estimate Fair Value of Employee Stock Option at Grant Date

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:  

	Nine Months Ended September 30,
	2016		2015
	(Unaudited)
Expected term (in years)		6.0		6.0
Expected volatility%		59.9%		68.7%
Risk-free interest rate%		1.3%		1.8%
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 September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
	(Unaudited)
Research and development	$	111	$	95	$	467	$	143
Selling and marketing		40		16		78		26
General and administrative		803		272		1,654		362
Total stock-based compensation expense	$	954	$	383	$	2,199	$	531