Stock-Based Awards (Tables)

3 Months Ended

Mar. 31, 2016

Stock-Based Awards

Assumptions used to determine fair value of stock options granted

	Three Months Ended
	March 31, 2016
Risk-free interest rate	1.49	%
Expected term (in years)	7.3
Expected volatility	99.97	%
Expected dividend yield	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, 2015	1,738,524			13.23	9.51	$	24,722
Granted	68,500			20.28
Exercised	—			—
Forfeited and canceled	—			—
Outstanding as of March 31, 2016	1,807,024		$	13.50	9.28	$	14,892
Options vested and expected to vest as of March 31, 2016	1,807,024		$	13.50	9.28	$	14,892
Options exercisable as of March 31, 2016	180,422	(1)	$	1.27	8.49	$	3,189

(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, 2016.

Summary of RSU activity

		Weighted
		Average
		Grant Date
	Number	Fair Value
	of Shares	Per Share
Outstanding at December 31, 2015	53,800	$	28.68
Granted	13,700		20.28
Vested	—		—
Forfeited and cancelled	—		—
Outstanding at March 31, 2016	67,500	$	26.98

Stock-based compensation expense

	Three Months Ended March 31,
	2016		2015
Research and development	$	421	$	13
General and administrative		801		30
	$	1,222	$	43