Net Loss Per Common Share - Schedule of Potentially Dilutive Securities Excluded from Diluted Net Loss Per Common Share (Details) - shares	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	1,692,014	3,854,375
Redeemable Convertible Preferred Stock
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share		2,486,199
Options to purchase common stock
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	1,481,632	878,948
Common stock subject to repurchase
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	182,692	461,538
Redeemable Convertible Preferred Stock Warrants
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share		27,690
Common Stock Warrants
Antidilutive Securities
Potentially dilutive securities excluded from diluted net loss per common share	27,690

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration