Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Fair Value of Employee and Director Stock Options Estimated Using Weighted Average Assumptions

The fair value of employee and director stock options was estimated at the date of grant using a Black-Scholes option valuation model with the weighted average assumptions below.

	Three Months Ended September 30						Nine Months Ended September 30
	2017			2016			2017			2016
Expected term (in years)		6.1			6.1			6.1			6.1
Expected volatility		46.9	%		60.0	%		52.1	%		60.0	%
Risk-free interest rate		1.94	%		1.28	%		2.07	%		1.45	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%

Summary of Total Stock-Based Compensation Expense Included in Statements of Operations and Comprehensive Loss

The following table summarizes the total stock-based compensation expense included in the statements of operations and comprehensive loss for all periods presented (in thousands):

	Three Months Ended September 30				Nine Months Ended September 30
	2017		2016		2017		2016
Cost of revenue	$	36	$	3	$	112	$	8
Research and development		446		34		1,198		103
Selling, general and administrative		2,249		364		5,714		1,140
Total stock-based compensation expense	$	2,731	$	401	$	7,024	$	1,251