Stock-Based Awards (Tables)

3 Months Ended

Mar. 31, 2019

Stock-Based Awards

Assumptions used to determine fair value of stock options granted

	Three Months Ended
	March 31,
	2019		2018
Risk-free interest rate	2.53	%	2.61	%
Expected term (in years)	6.3		6.3
Expected volatility	101.70	%	95.60	%
Expected dividend yield	0	%	0	%

Summary of stock option activity

					Weighted
			Weighted		Average
			Average		Remaining	Aggregate
	Number		Exercise		Contractual	Intrinsic
	of Shares		Price		Term	Value
					(in years)
Outstanding as of December 31, 2018	4,282,081		$	20.53	7.91	$	2,404
Granted	28,500			7.66
Exercised	—			—
Forfeited and cancelled	(127,997)			24.38
Outstanding as of March 31, 2019	4,182,584		$	20.32	7.53	$	1,850
Options vested and expected to vest as of March 31, 2019	4,182,584		$	20.32	7.53	$	1,850
Options exercisable as of March 31, 2019	2,205,639	(1)	$	17.92	6.75	$	1,850

(1) All options granted under the 2012 Plan are exercisable immediately, subject to a repurchase right in the Company’s favor that lapses as the option vests. This amount reflects the number of shares under options that were vested, as opposed to exercisable, as of March  31, 2019.

Summary of restricted stock units activity

		Weighted
		Average
		Grant Date
	Number	Fair Value
	of Shares	Per Share
Outstanding as of December 31, 2018	626,407	$	20.30
Granted	1,441,444		6.34
Vested	(85,677)		22.39
Forfeited and cancelled	(14,151)		20.08
Outstanding as of March 31, 2019	1,968,023	$	9.99

Stock-based compensation expense

	Three Months Ended
	March 31,
	2019		2018
Cost of revenue	$	206	$	176
Research and development		1,594		1,727
Sales and marketing		590		907
General and administrative		2,472		2,333
Total stock-based compensation expense	$	4,862	$	5,143