Balance Sheet Components - Summary of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Cost	$ 71,437	$ 102,015
Unrealized (Loss)	(69)
Estimated Fair Value	71,368	102,015
Money market funds
Schedule Of Available For Sale Securities [Line Items]
Cost	5,548	102,015
Estimated Fair Value	5,548	102,015
U.S. treasury securities
Schedule Of Available For Sale Securities [Line Items]
Cost	4,334
Unrealized (Loss)	(5)
Estimated Fair Value	4,329
U.S. government agency securities
Schedule Of Available For Sale Securities [Line Items]
Cost	38,369
Unrealized (Loss)	(29)
Estimated Fair Value	38,340
Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	5,502	101,969
Short-term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	63,823
Long-term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	1,997
Restricted Cash
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	46	$ 46
Corporate notes and commercial paper
Schedule Of Available For Sale Securities [Line Items]
Cost	23,186
Unrealized (Loss)	(35)
Estimated Fair Value	$ 23,151

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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