Balance Sheet Components - Balance Sheet Details (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Inventories:
Raw materials	$ 34,867		$ 32,511
Work in process	7,867		8,726
Finished goods	61,172		59,631
Total inventories	103,906		100,868
Other long-term assets:
Capitalized software, net	71,434		56,819
Unbilled receivables	13,630		16,481
Other assets	1,103		1,313
Total other long-term assets, net	86,167		74,613
Accrued liabilities:
Current lease liability	10,286	$ 10,300	0
Advance payments from customers	6,494		8,993
Rebates and lease buyouts	13,031		11,076
Group purchasing organization fees	4,668		4,455
Taxes payable	4,038		5,885
Other accrued liabilities	16,053		12,638
Total accrued liabilities	$ 54,570		$ 43,047