Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Percentage of total revenue accounted for percentage-of-completion revenue, less than	0.10%	0.10%	0.10%	0.10%
Product sales as a percentage of total revenue	95.00%	95.00%	95.00%	95.00%
Disaggregation of Revenue [Line Items]
Revenue	$ 21,879	$ 53,709	$ 99,827	$ 134,324
Operating expenses (excluding depreciation and amortization):	23,689	45,647	106,593	117,848
Products
Disaggregation of Revenue [Line Items]
Revenue	21,031	52,510	96,733	130,652
Operating expenses (excluding depreciation and amortization):	23,637	44,048	105,440	114,365
Services
Disaggregation of Revenue [Line Items]
Revenue	848	1,199	3,094	3,672
Operating expenses (excluding depreciation and amortization):	$ 52	$ 1,599	$ 1,153	$ 3,483