Balance Sheet Components - Product Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Movement in Extended Product Warranty Accrual [Roll Forward]
Balance at the beginning of the period	$ 2,901	$ 3,215	$ 2,902	$ 3,272
Extended warranties issued	1,215	1,073	2,219	1,806
Amortization	(1,044)	(903)	(2,049)	(1,693)
Balance at the end of the period	3,072	3,385	3,072	3,385
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at the beginning of the period	1,052	440	527	569
Settlements of warranties	(248)	33	(473)	(67)
Provision	624	(134)	1,374	(163)
Balance at the end of the period	$ 1,428	$ 339	$ 1,428	$ 339
Direct Customer [Member] | Control Units [Member]
Product Liability Contingency [Line Items]
Standard limited warranty (years)			1 year
Direct Customer [Member] | Applicators [Member]
Product Liability Contingency [Line Items]
Standard limited warranty (years)			1 year
International [Member] | Indirect Customer [Member] | Control Units [Member]
Product Liability Contingency [Line Items]
Standard limited warranty (years)			3 years 2 months
International [Member] | Indirect Customer [Member] | Applicators [Member]
Product Liability Contingency [Line Items]
Standard limited warranty (years)			1 year 2 months