Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Stock-Based Compensation

Summary of stock option activity

	Outstanding Options
					Weighted-
			Weighted-		Average
	Shares		Average		Remaining	Aggregate
	Available for	Number of	Exercise		Contractual	Intrinsic
(in thousands, except for contractual life and exercise price)	Grant	Shares	Price		Life	Value
					(In years)
Balance at December 31, 2015	3,743	9,316	$	3.96
Additional shares authorized	2,014	—
Options granted	(2,199)	2,199	$	10.06
Options exercised	—	(1,618)	$	1.68
Options forfeited/cancelled	751	(751)	$	8.15
Balance at September 30, 2016	4,309	9,146	$	5.47	7.70	$	53,338
Exercisable at September 30, 2016		4,819	$	2.75	6.59	$	40,763
Vested and expected to vest at September 30, 2016		8,761	$	5.33	7.62	$	52,219

Restricted stock units

			Weighted-
			Average
			Grant Date
(in thousands, except for grant date fair value)	Shares		Fair Value
Balance at December 31, 2015	—		—
Granted	210	$	9.75
Vested	(25)	$	9.59
Canceled/forfeited	(11)	$	9.74
Balance at September 30, 2016	174	$	9.78

Summary of stock-based compensation expenses

	Three months ended  September 30,
	2016						2015
	Employee		Non-Employee		Total		Employee		Non-Employee		Total
	(in thousands)
Cost of revenues	$	164	$	(4)	$	160	$	400	$	10	$	410
Research and development		784		(1)		783		266		2		268
Selling, general and administrative		1,716		14		1,730		1,491		(3)		1,488
Total	$	2,664	$	9	$	2,673	$	2,157	$	9	$	2,166

	Nine months ended September 30,
	2016						2015
	Employee		Non-Employee		Total		Employee		Non-Employee		Total
	(in thousands)
Cost of revenues	$	479	$	3	$	482	$	549	$	217	$	766
Research and development		2,105		(1)		2,104		824		24		848
Selling, general and administrative		5,117		262		5,379		3,202		90		3,292
Total	$	7,701	$	264	$	7,965	$	4,575	$	331	$	4,906

Schedule of assumptions used in valuation of fair value of employee stock options

	Three months ended  September 30,										Nine months ended September 30,
	2016					2015					2016					2015
Expected term				5.2		5.7		—	6.1		5.1		—	5.2		5.6		—	6.5
Expected volatility	69.0	%	—	72.5	%	69.7	%	—	71.9	%	68.5	%	—	72.5	%	69.7	%	—	78.8	%
Expected dividend rate				0	%				0	%				0	%				0	%
Risk-free interest rate	0.97	%	—	1.12	%	1.65	%	—	1.80	%	0.97	%	—	1.24	%	1.56	%	—	1.96	%