Stockholders' Equity (Summary of Stock-based Compensation) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based compensation
Stock-based compensation expense	$ 844	$ 958	$ 1,611	$ 2,106
Cost of revenues
Share-based compensation
Stock-based compensation expense	2	133	14	299
Sales and marketing
Share-based compensation
Stock-based compensation expense	116	49	228	130
Research and development
Share-based compensation
Stock-based compensation expense	180	201	314	458
General and administrative
Share-based compensation
Stock-based compensation expense	$ 546	$ 575	$ 1,055	$ 1,219