Summary of Significant Accounting Policies - Summary of Fair Value Measurement Financial Asset and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets [Abstract]
Cash and cash equivalents	$ 108,000
Restricted cash	0	$ 300
Total Assets	250,831	26,346
Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	62,353	26,046
U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	9,348
Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	41,202
Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	137,928
Quoted Prices in Active Markets for Identical Assets Level 1 [Member]
Assets [Abstract]
Restricted cash		300
Total Assets	62,353	26,346
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	62,353	26,046
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Quoted Prices in Active Markets for Identical Assets Level 1 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Other Observable Inputs, Level 2 [Member]
Assets [Abstract]
Restricted cash		0
Total Assets	188,478	0
Significant Other Observable Inputs, Level 2 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Significant Other Observable Inputs, Level 2 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	9,348
Significant Other Observable Inputs, Level 2 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	41,202
Significant Other Observable Inputs, Level 2 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	137,928
Significant Unobservable Inputs, Level 3 [Member]
Assets [Abstract]
Restricted cash		0
Total Assets	0	0
Significant Unobservable Inputs, Level 3 [Member] \| Money Market Funds [Member]
Assets [Abstract]
Cash and cash equivalents	0	$ 0
Significant Unobservable Inputs, Level 3 [Member] \| U.S. Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Unobservable Inputs, Level 3 [Member] \| Government-sponsored Enterprises [Member]
Assets [Abstract]
Available-for-sale Securities, Current	0
Significant Unobservable Inputs, Level 3 [Member] \| Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Current	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

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
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ 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 210.5-02.1)
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