Equity Award Plan Activities - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		9 Months Ended
Feb. 17, 2015	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense		$ 95.4
Approved increase of shares available (in shares)		2,044,000
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average amortization period		3 years 11 months
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average amortization period		3 years 3 months
Unrecognized stock-based compensation expense for unvested options, net of expected forfeitures		$ 61.4
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average amortization period		1 year 9 months
Unrecognized stock-based compensation expense for unvested options, net of expected forfeitures		$ 6.1
ESPP shares purchased (in shares)		256,223
Weighted-average price of ESPP shares purchased (in usd per share)		$ 40.30
Increase of shares available for issuance as a percent	1.00%
Maximum number of additional shares for authorization	2,500,000
Approved increase of shares available (in shares)		681,315
Employee Stock Purchase Plan \| 2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant beginning balance (in shares)		1,483,846

Percent of Shares Outstanding to Increase Number of Shares Available for Grant and Issuance

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Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Additional Shares to be Authorized

+ References

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested options awarded to employees as compensation.

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Number of additional shares authorized for issuance under an established share-based compensation plan.

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- Definition

The weighted average of per share prices paid for shares purchased on the open market for issuance to employees under the plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The number of shares purchased on the open market during the period for issuance to employees under the plan.

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-Name Accounting Standards Codification
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Number of shares issued during the period as a result of an employee stock purchase plan.

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-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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-Paragraph 29, 30
-Article 5

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