Debt - Credit Facilities (Details) - Borrowing under Wells Fargo Credit Facility - USD ($)	1 Months Ended	3 Months Ended
	Sep. 30, 2017	Mar. 31, 2021	Dec. 31, 2020	Jun. 14, 2019
Line of Credit Facility [Line Items]
Accrued interest included in balance		$ 100,000
Line of credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing amount	$ 50,000,000.0
Cash balance for borrowing	100.00%
Cash balance max borrowing (up to)	$ 15,000,000.0
Maximum revolver increase	$ 25,000,000.0
Commitment fee	0.25%
Maximum indebtedness under debt covenant	$ 20,000,000.0
Unused borrowing capacity	$ 5,000,000.0			$ 5,000,000.0
Outstanding balance of line of credit facilities		$ 21,100,000
Weighted average interest rate		1.96%	2.01%
Unused part of credit facility		$ 9,000,000.0
Minimum required unused borrowing capacity		$ 5,000,000.0
Line of credit | U.S.
Line of Credit Facility [Line Items]
Liquidity requirements under line of credit facility				30,000,000.0
Line of credit | World wide
Line of Credit Facility [Line Items]
Liquidity requirements under line of credit facility				$ 40,000,000.0
Line of credit | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Weighted average interest rate		1.96%
Line of credit | Minimum
Line of Credit Facility [Line Items]
Revolver accounts receivable	80.00%
Line of credit | Minimum | Base Rate
Line of Credit Facility [Line Items]
Interest rate spread	1.50%
Line of credit | Minimum | Prime rate
Line of Credit Facility [Line Items]
Interest rate spread	0.50%
Line of credit | Maximum
Line of Credit Facility [Line Items]
Revolver accounts receivable	85.00%
Line of credit | Maximum | Base Rate
Line of Credit Facility [Line Items]
Interest rate spread	1.75%
Line of credit | Maximum | Prime rate
Line of Credit Facility [Line Items]
Interest rate spread	0.75%