Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 7,978	$ 4,976
Work-in-process	9,505	5,087
Finished products	15,985	23,155
Field inventory	22,021	17,593
Consignment inventory	4,428	2,199
Deferred cost of sales	3,429	4,553
Total inventory	$ 63,346	$ 57,563