Stock-Based Awards (Tables)

12 Months Ended

Dec. 31, 2015

Stock-Based Awards

Assumptions used to determine fair value of stock options granted

	Year Ended		Year Ended
	December 31, 2015		December 31, 2014
Risk-free interest rate	1.78	%	1.87	%
Expected term (in years)	6.3		6.4
Expected volatility	93.9	%	113.9	%
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 January 1, 2013	—			—	—		—
Granted	—			—
Exercised	—			—
Forfeited and canceled	—			—
Outstanding as of December 31, 2013	—			—	—		—
Granted	500,262		$	1.22
Exercised	—			—
Forfeited and canceled	—			—
Outstanding as of December 31, 2014	500,262			1.22	9.77	$	305
Granted	1,238,262			18.08
Exercised	—			—
Forfeited and canceled	—			—
Outstanding as of December 31, 2015	1,738,524		$	13.23	9.51	$	24,722
Options vested and expected to vest as of December 31, 2015	1,738,524		$	13.23	9.51	$	24,722
Options exercisable as of December 31, 2015	147,672	(1)	$	1.19	8.72	$	3,803

(1) All options granted to date 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 December 31, 2015.

Summary of RSU activity

		Weighted
		Average
		Grant Date
	Number	Fair Value
	of Shares	Per Share
Outstanding at December 31, 2014	—	$	—
Granted	53,800		28.68
Vested	—		—
Forfeited and cancelled	—		—
Outstanding at December 31, 2015	53,800	$	28.68

Stock-based compensation expense

	Year Ended
	December 31,
	2015		2014		2013
Research and development	$	257	$	10	$	—
General and administrative		634		17		—
	$	891	$	27	$	—