Impairment of Field Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of field equipment	$ 6,412	$ 6,412
First Generation Optune System Field Equipment | Cost of Revenues
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of field equipment	6,412	6,412
Advances for materials purchased and liabilities incurred to vendors	$ 1,582	$ 1,582