Leasing Arrangements - Components of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1,169	$ 1,261	$ 2,343	$ 2,413
Amortization of finance lease assets	5	3	10	49
Interest on finance lease liabilities	1	1	1	8
Short-term lease cost	29	16	70	27
Variable lease cost	398	793	874	793
Sublease income	(6)	(6)	(24)	(6)
Total lease cost	1,596	2,068	3,274	3,284
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Total lease cost	800	1,100	1,700	1,700
Cost of Sales
Lessee, Lease, Description [Line Items]
Total lease cost	400	400	800	800
Research and Development Expense
Lessee, Lease, Description [Line Items]
Total lease cost	$ 400	$ 500	$ 800	$ 800