Consolidated Balance Sheet Components - Allowance for Doubtful Accounts (Detail) (Allowance for doubtful accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for doubtful accounts, beginning balance	$ 410	$ 412	$ 225
Charged to costs and expenses	418	46	269
Deductions (write-offs)	(613)	(48)	(82)
Allowance for doubtful accounts, ending balance	$ 215	$ 410	$ 412