Stock-Based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	$ 2,291	$ 2,273	$ 4,594	$ 4,191
Income tax benefit	500	477	1,006	876
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	36	37	110	65
Research and development expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	288	274	524	494
Selling, general and administrative expenses | Employees
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	1,557	1,715	3,140	3,139
Selling, general and administrative expenses | Outside directors
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	$ 410	$ 247	$ 820	$ 493