Details of Selected Balance Sheet Accounts - Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of inventories:
Raw materials and purchased subassemblies	$ 21,454	$ 34,949
Work-in-process	2,255	8,478
Finished goods	6,581	13,769
Reserve for excess and obsolete inventories	(15,049)	(24,475)
Total	15,241	32,721
Property, Plant and Equipment [Line Items]
Transfer of inventory to property, plant and equipment	17,662	$ 15,936	$ 10,149
Ocean Bottom Services [Member]
Property, Plant and Equipment [Line Items]
Transfer of inventory to property, plant and equipment	17,700
Increase in reserve for excess and obsolete inventories	$ 400