Stock Option Plans - Share-based Payment Agreement, Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 104	$ 137	$ 236	$ 276
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	11	10	26	20
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	40	43	86	86
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	5	7	12	16
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 48	$ 77	$ 112	$ 154