Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	$ 7,137	$ 6,852
Cost of revenue - product
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	182	309
Cost of revenue - service
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	763	984
Research and development
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	1,409	2,282
Sales and marketing
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	528	987
General and administrative
Stock-based compensation expense
Total stock-based compensation expense (in dollars)	$ 4,255	$ 2,290