Stock-Based Compensation - Distribution of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share Based Compensation Expense [Line Items]
Stock-based compensation	$ 367	$ 337	$ 1,136	$ 1,021
Cost of Revenue
Share Based Compensation Expense [Line Items]
Stock-based compensation	33	29	100	83
Research and Development
Share Based Compensation Expense [Line Items]
Stock-based compensation	133	124	401	370
Selling, General and Administrative
Share Based Compensation Expense [Line Items]
Stock-based compensation	$ 201	$ 184	$ 635	$ 568