Balance Sheet Components - Balance Sheet Details (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventories:
Raw materials	$ 32,529	$ 31,275
Work in process	9,929	8,718
Finished goods	56,773	56,144
Total inventories	99,231	96,137
Property and equipment:
Equipment	77,837	69,550
Furniture and fixtures	7,961	6,534
Leasehold improvements	16,209	10,976
Software	39,611	37,168
Construction in progress	11,428	9,813
Property and equipment, gross	153,046	134,041
Accumulated depreciation and amortization	(102,562)	(91,446)
Total property and equipment, net	50,484	42,595
Other long term assets:
Capitalized software, net	52,088	38,599
Unbilled receivables	15,573	9,475
Other assets	1,287	1,242
Total other long term assets, net	68,948	49,316
Accrued liabilities:
Advance payments from customers	4,850	7,779
Rebates and lease buyouts	8,273	5,428
Group purchasing organization fees	4,023	3,449
Taxes payable	5,770	9,183
Other accrued liabilities	12,861	9,854
Total accrued liabilities	$ 35,777	$ 35,693