Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

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

Stock-Based Compensation Expense

Stock-based compensation expense was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cost of revenues	$	58	$	53	$	173	$	125
Selling, general and administrative		474		466		1,973		861
Research and development		156		212		458		286
Total stock-based compensation	$	688	$	731	$	2,604	$	1,272

Summary of Compensation Expense by Type of Award

Compensation expense by type of award was as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Stock options	$	503	$	689	$	2,101	$	1,230
ESPP		185		42		503		42
Total stock-based compensation	$	688	$	731	$	2,604	$	1,272