Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock-based Awards for 2008 Plan and 2015 Plan

The following table provides a summary of stock-based awards for the 2008 Plan and 2015 Plan (the “Plans”) for the nine months ended September 30, 2018 and 2017:

	Nine months ended September 30, 2018									Nine months ended September 30, 2017
	Stock Options			RSUs			Total			Stock Options			RSUs			Total
Outstanding as of December 31		1,916,832			86,875			2,003,707			2,129,856			—			2,129,856
Granted		1,016,720			120,000			1,136,720			42,500			122,588			165,088
Exercised		(175,407	)		(37,500	)		(212,907	)		(118,213	)		(72,361	)		(190,574	)
Forfeited		(123,850	)		—			(123,850	)		(447,065	)		(227	)		(447,292	)
Outstanding as of September 30		2,634,295			169,375			2,803,670			1,607,078			50,000			1,657,078

Stock-based Compensation Expense included in Accompanying Statements of Operations and Comprehensive Loss

Stock-based compensation expense is included in the following line items in the accompanying statements of operations and comprehensive loss for the three and nine months ended September 30, 2018 and 2017 (in thousands):

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Research and development	$	813	$	38	$	1,186	$	112
General and administrative		1,175		76		1,606		238
Total stock-based compensation	$	1,988	$	114	$	2,792	$	350