Convertible Preferred Stock (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock
Common stock, shares authorized	750,000,000	750,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000		51,233
Convertible preferred stock, shares outstanding		0	31,397,221	31,397
Liquidation Amount				$ 133,757
Proceeds, net of Issuance Costs				240,612
Convertible preferred stock
Stock
Proceeds, net of Issuance Costs				$ 240,612,000	$ 185,199,000
A-1
Stock
Preferred stock, shares authorized				5,000
Convertible preferred stock, shares outstanding				3,067
Liquidation Amount				$ 20
Proceeds, net of Issuance Costs				$ 20
A
Stock
Preferred stock, shares authorized				8,173
Convertible preferred stock, shares outstanding				5,014
Liquidation Amount				$ 4,005
Proceeds, net of Issuance Costs				$ 3,927
B
Stock
Preferred stock, shares authorized				5,745
Convertible preferred stock, shares outstanding				3,491
Liquidation Amount				$ 6,600
Proceeds, net of Issuance Costs				$ 6,569
C
Stock
Preferred stock, shares authorized				8,941
Convertible preferred stock, shares outstanding				5,485
Liquidation Amount				$ 12,160
Proceeds, net of Issuance Costs				$ 58,876
D
Stock
Preferred stock, shares authorized				6,694
Convertible preferred stock, shares outstanding				4,107
Liquidation Amount				$ 20,047
Proceeds, net of Issuance Costs				$ 80,788
E
Stock
Preferred stock, shares authorized				9,592
Convertible preferred stock, shares outstanding				5,884
Liquidation Amount				$ 35,425
Proceeds, net of Issuance Costs				$ 35,019
F
Stock
Preferred stock, shares authorized				7,088
Convertible preferred stock, shares outstanding				4,349
Liquidation Amount				$ 55,500
Proceeds, net of Issuance Costs				$ 55,413