Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2015

Equity Incentive Plans

Schedule of stock-based compensation expense and allocation

	Year Ended December 31,
	2015		2014		2013
Employee	$	2,662	$	1,185	$	476
Non-employee		303		196		862
Total	$	2,965	$	1,381	$	1,338

	Year Ended December 31,
	2015		2014		2013
Research and development	$	1,161	$	617	$	862
General and administrative		1,804		764		476
Total stock-based compensation expense	$	2,965	$	1,381	$	1,338

Schedule of assumptions used to compute employee stock-based compensation

	2015			2014			2013
Risk-free interest rate		1.92	%		1.84	%		1.73	%
Expected volatility		75.0	%		104.8	%		104.8	%
Expected dividend yield		0	%		0	%		0	%
Expected life (in years)		6.25			6.25			6.25

Summary of options outstanding, vested and exercisable

	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Options outstanding at December 31, 2013		1,163,621			3.44	7.9 years
Options granted		712,570			8.76
Options exercised		(41,904	)		1.61
Options cancelled/forfeited		(16,739	)		4.65
Options outstanding at December 31, 2014		1,817,548			5.56	7.9 years
Options granted		620,600			9.84
Options exercised		(261,936	)		2.26
Options cancelled/forfeited		(11,147	)		2.14
Options outstanding at December 31, 2015		2,165,065			7.19	7.8 years	$	6,459
Options exercisable at December 31, 2015		1,083,249			5.06	6.7 years	$	5,622
Vested and expected to vest at December 31, 2015		2,165,065			7.19	7.8 years