Discontinued Operations - Additional Information (Details) $ in Thousands		3 Months Ended
	Sep. 01, 2016 option	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contracts revenue		$ 24,555	$ 21,307
Cost of revenues		7,987	6,402
Supply agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contracts revenue		1,600	2,100
Cost of revenues		$ 1,400	$ 2,000
Discontinued operations, disposed of by sale | International Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Supply commitment term	3 years
Supply agreement, number of annual options to extend | option	2
Supply agreement, extended term		12 months
Supply agreement, extended period		2020-08