Stockholders' Equity Common Stock (Tables)

3 Months Ended

Mar. 31, 2017

Equity [Abstract]

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity since December 31, 2016:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)
Outstanding as of December 31, 2016		5,069,133		$	14.36		8.26	$	16,736
Granted		1,287,500			9.88
Exercised		(31,125	)		0.62
Forfeited		(74,156	)		22.73
Outstanding as of March 31, 2017		6,251,352		$	13.41		8.38	$	21,138
Options exercisable as of March 31, 2017		2,383,405		$	9.82		7.58	$	13,367

Summary of Restricted Stock Activity

The Company has granted restricted stock units with time-based vesting conditions.  The table below summarizes the Company’s restricted stock activity for the three months ended March 31, 2017:

	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock units as of December 31, 2016		115,500		$	9.78
Granted		292,500		$	9.98
Forfeited		(2,800	)	$	9.78
Vested		—		$	—
Unvested restricted stock units as of March 31, 2017		405,200		$	9.92

Summary of Stock Based Compensation Expense

The Company recorded stock-based compensation expense related to stock options and restricted stock units in the following expense categories of its consolidated statements of operations and comprehensive loss:

	Three Months Ended March 31,
	2017		2016
Research and development expenses	$	1,873	$	2,186
General and administrative expenses		2,406		1,718
	$	4,279	$	3,904