Balance Sheet Components - Balance Sheet Details (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Inventories:
Raw materials	$ 31,780		$ 32,511
Work in process	8,720		8,726
Finished goods	65,313		59,631
Total inventories	105,813		100,868
Other long-term assets:
Capitalized software, net	78,409		56,819
Unbilled receivables	12,794		16,481
Other assets	1,056		1,313
Total other long-term assets, net	92,259		74,613
Accrued liabilities:
Operating lease liabilities, current portion	10,281	$ 10,300	0
Advance payments from customers	4,865		8,993
Rebates and lease buyouts	17,551		11,076
Group purchasing organization fees	5,423		4,455
Taxes payable	3,556		5,885
Other accrued liabilities	16,341		12,638
Total accrued liabilities	$ 58,017		$ 43,047