Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Distribution of Stock-Based Compensation Expense

The following table summarizes the distribution of stock-based compensation expense (in thousands):

	Three Months Ended
	March 31,
	2019		2018
Cost of revenue	$	25	$	9
Research and development		122		87
Selling, general and administrative		189		174
Total	$	336	$	270