Stock-Based Compensation - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	$ 3,117	$ 2,025	$ 7,933	$ 5,097
Cost of Sales
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	270	241	770	620
Cost of Sales | Product
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	170	143	482	351
Cost of Sales | Service
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	100	98	288	269
Selling and Marketing Expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	356	411	1,110	1,123
General and Administrative Expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	2,389	1,172	5,942	2,808
Research and Development Expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Allocated share-based compensation expense	$ 372	$ 442	$ 881	$ 1,166