Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - Summary of Preferred Stock Warrants Outstanding Exercise Price (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) shares
June 2, 2010 Series 2 Preferred Stock
Redeemable Convertible Preferred Stock and Stockholders Deficit Equity [Line Items]
Preferred stock warrants Issuance date	Jun. 02, 2010	[1]
Warrants outstanding | shares	2,004	[1]
Fair value of preferred stock warrants | $	$ 24	[1]
February 1, 2011 Series 2 Preferred Stock
Redeemable Convertible Preferred Stock and Stockholders Deficit Equity [Line Items]
Preferred stock warrants Issuance date	Feb. 01, 2011	[1]
Warrants outstanding | shares	1,458	[1]
Fair value of preferred stock warrants | $	$ 18	[1]
July 13, 2012 Series 2 Preferred Stock
Redeemable Convertible Preferred Stock and Stockholders Deficit Equity [Line Items]
Preferred stock warrants Issuance date	Jul. 13, 2012	[1]
Warrants outstanding | shares	41,666	[1]
Fair value of preferred stock warrants | $	$ 548	[1]
June 30, 2010 Series 2 Preferred Stock
Redeemable Convertible Preferred Stock and Stockholders Deficit Equity [Line Items]
Preferred stock warrants Issuance date	Jun. 30, 2010	[2]
Warrants outstanding | shares	218,523	[2]
Fair value of preferred stock warrants | $	$ 2,275	[2]
Series 2 Redeemable Convertible Preferred Stock
Redeemable Convertible Preferred Stock and Stockholders Deficit Equity [Line Items]
Warrants outstanding | shares	263,651
Fair value of preferred stock warrants | $	$ 2,865

[1] These warrants exercised on a net exercise basis in July 2016.

[2] These warrants either were exercised prior to our initial public offering or automatically exercised on a net exercise basis as the per share price of common stock sold to the public in our initial public offering exceeded the exercise price of the warrants.