Leasing Arrangements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Lessee, Lease, Description [Line Items]
Lease cost	$ 1,215
Operating lease, rent expense		$ 800
Selling, General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Lease cost	600
Cost of Sales
Lessee, Lease, Description [Line Items]
Lease cost	300
Research and Development Expense
Lessee, Lease, Description [Line Items]
Lease cost	$ 300