Debt (Narrative) (Details)			1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 18, 2020 USD ($) $ / shares	Apr. 29, 2020 USD ($)	Jun. 30, 2015	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Dec. 01, 2017 USD ($)
Line of Credit Facility [Line Items]
Credit facility default interest rate						2.00%
Credit facility aggregate interest rate						4.50%
Credit facility commitment fee percentage						0.50%
Credit facility repayments							$ 30,000,000
Proceeds from issuance of convertible debt							100,000,000
Debt issuance costs						$ 2,219,000	3,647,000
Interest expense						16,900,000	16,700,000	$ 14,900,000
Interest Expense [Member]
Line of Credit Facility [Line Items]
Debt issuance costs						361,000
Debt extinguishment costs						$ 474,000
Government Sponsored Debt [Member]
Line of Credit Facility [Line Items]
Loan term			9 years
2.45% Sparkasse Zollernalb (KFW Loan 1) [Member]
Line of Credit Facility [Line Items]
Interest rate on amounts borrowed			2.45%			2.45%
1.40% Sparkasse Zollernalb (KFW Loan 2) [Member]
Line of Credit Facility [Line Items]
Interest rate on amounts borrowed			1.40%			1.40%
Convertible Senior Notes [Member]
Line of Credit Facility [Line Items]
Credit facility repayments							30,000,000.0
Face value	$ 100,000,000.0
Notes payable						$ 100,000,000.0
Interest rate on amounts borrowed	4.25%
Maturity date						Jul. 01, 2025
Proceeds from issuance of convertible debt	$ 96,500,000
Conversion ratio	42.6203
Conversion principal amount	$ 1,000
Conversion price | $ / shares	$ 23.46
Debt fair value						$ 116,000,000.0
Effective interest rate						5.05%
Interest expense						$ 4,900,000	4,200,000
Unamortized debt issuance costs						$ 2,500,000
Convertible Senior Notes [Member] | Circumstance I [Member]
Line of Credit Facility [Line Items]
Conversion trading day threshold | item						20
Conversion consecutive trading day threshold | item						30
Conversion percentage of stock price threshold						130.00%
Convertible Senior Notes [Member] | Circumstance II [Member]
Line of Credit Facility [Line Items]
Conversion principal amount						$ 1,000
Conversion trading day threshold | item						5
Conversion consecutive trading day threshold | item						5
Conversion percentage of stock price threshold						98.00%
Convertible Senior Notes [Member] | Circumstance After July 5, 2023 [Member]
Line of Credit Facility [Line Items]
Conversion trading day threshold | item						20
Conversion consecutive trading day threshold | item						30
Conversion percentage of stock price threshold						130.00%
Conversion percentage of principal amount						100.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility aggregate commitments										$ 30,000,000.0
Credit facility maturity date						Dec. 01, 2022
Credit facility outstanding balance									$ 30,000,000.0
Credit facility aggregate interest rate									5.20%
Credit facility repayments							$ 30,000,000.0
Line of credit facility, percentage threshold of principal amount outstanding						25.00%
Revolving Credit Facility [Member] | Amended Credit Agreement [Member]
Line of Credit Facility [Line Items]
Maximum percentage allowed for total principal amount of loans		25.00%
Maximum principal amount of loans outstanding		$ 7,500,000
First lien net leverage ratio		3.4
Minimum liquidity requirement		$ 12,000,000.0
Revolving Credit Facility [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Credit facility margin						3.00%
Revolving Credit Facility [Member] | Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility margin						4.00%
Revolving Credit Facility [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Credit facility margin						3.25%
Revolving Credit Facility [Member] | Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility margin						4.25%
Secured Debt [Member]
Line of Credit Facility [Line Items]
Credit facility aggregate commitments										255,000,000.0
Credit facility outstanding balance										$ 225,000,000.0
Term Loan [Member]
Line of Credit Facility [Line Items]
Credit facility maturity date						Dec. 01, 2024
Term Loan [Member] | Amended Credit Agreement Two [Member] | Circumstance I [Member]
Line of Credit Facility [Line Items]
Debt instrument, extension circumstance period						91 days
Term Loan [Member] | Amended Credit Agreement Two [Member] | Circumstance II [Member]
Line of Credit Facility [Line Items]
Debt instrument, extension circumstance period						182 days
Term Loan [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Credit facility margin				2.25%	3.00%	2.25%
Term Loan [Member] | Base Rate [Member] | Amended Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
Credit facility margin						2.50%
Term Loan [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Credit facility margin				3.25%	4.00%	3.25%
Term Loan [Member] | LIBOR [Member] | Amended Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
Credit facility margin						3.50%
Revolving Credit Facility And Term Loan [Member]
Line of Credit Facility [Line Items]
Debt issuance costs						$ 2,100,000
Amortization of the debt issuance costs						$ 1,800,000
Revolving Credit Facility And Term Loan [Member] | Amended Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
Debt instrument, extension period						2 years 6 months
Revolving Credit Facility And Term Loan [Member] | Convertible Senior Notes [Member] | Amended Credit Agreement Two [Member]
Line of Credit Facility [Line Items]
Interest rate on amounts borrowed						4.25%