Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock-based compensation expense

Stock-based compensation expense is included in the consolidated statements of operations as follows (in thousands):

	Three Months Ended March 31,
	2017		2016
Research and development	$	323	$	220
Selling, general and administrative	1,346		1,169
Total	$	1,669	$	1,389

Schedule of stock-based compensation expense by security types

The following table presents total stock-based compensation expense by security types included in the condensed consolidated statements of operations for the three months ended March 31, 2017 and 2016 (in thousands):

	Three Months Ended March 31,
	2017		2016
Stock options	$	334	$	304
RSUs and RSAs	459		574
PSUs	641		511
PBOs	235		—
Total	$	1,669	$	1,389

Valuation assumptions

The weighted-average assumptions used to estimate the fair value of employee stock options and PBOs granted were as follows:

	Three Months Ended March 31,
	2017			2016
Expected term (in years)	5.3			5.4
Volatility	62		%	65		%
Risk-free interest rate	2.00		%	1.30		%
Dividend yield	—		%	—		%
Weighted-average estimated fair value of stock options granted	$	2.52		$	2.31