Formation and Business of the Company - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			9 Months Ended
	Oct. 03, 2016	Nov. 03, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Accumulated deficit			$ (92,096)		$ (64,685)
Cash and cash equivalents			77,120	$ 64,545	$ 112,265	$ 43,648
Net proceeds from initial public offering		$ 55,600
Net proceeds from issuance of common stock			226	$ 352
Series A, A-1 and Series B Redeemable Convertible Preferred Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Net proceeds from sale of shares of convertible stock			$ 93,900
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock		6,253,125
Shares issued, price per share		$ 10.00
Follow-on Public Offering | Subsequent Event
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Issuance of common stock	4,370,000
Shares issued, price per share	$ 15.00
Net proceeds from issuance of common stock	$ 61,000