Stock-Based Compensation - Stock-based Compensation Expense and Related Income Tax Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	$ 2,260	$ 2,527	$ 6,854	$ 6,718
Income tax benefit	494	509	1,500	1,385
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	36	37	146	102
Research and development expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee and director stock-based compensation expense	287	315	811	809
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	1,555	1,866	4,695	5,005
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	$ 382	$ 309	$ 1,202	$ 802