Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Mar. 13, 2015	Dec. 31, 2015	Dec. 31, 2016	Jun. 30, 2015
Convertible Preferred Stock
Authorized shares of preferred stock (in shares)		5,000,000	5,000,000
Issuance of preferred stock (in shares)		0	0
Proceeds from issuance of preferred stock		$ 12,331
Preferred stock, outstanding (in shares)		0	0
Initial public offering
Convertible Preferred Stock
Issuance of preferred stock (in shares)				9,029,549
Share price (in dollars per share)				$ 12.00
Series B Convertible Preferred Stock
Convertible Preferred Stock
Authorized shares of preferred stock (in shares)	56,026,590
Issuance of preferred stock (in shares)	13,062,965
Share price (in dollars per share)	$ 0.9503
Proceeds from issuance of preferred stock	$ 12,300
Series B Convertible Preferred Stock | Initial public offering
Convertible Preferred Stock
Authorized shares of preferred stock (in shares)			5,000,000.0000
Issuance of preferred stock (in shares)			0
Share price (in dollars per share)			$ 0.001
Preferred stock, outstanding (in shares)			0