Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	$ 7,173	$ 6,906	$ 14,310	$ 13,758
Cost of revenue - product
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	193	313	375	622
Cost of revenue - service
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	839	994	1,602	1,978
Research and development
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	1,071	1,806	2,480	4,088
Sales and marketing
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	523	1,105	1,051	2,092
General and administrative
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	$ 4,547	$ 2,688	$ 8,802	$ 4,978