Convertible Preferred Stock (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($) director $ / shares shares	Dec. 31, 2015 $ / shares shares	Jul. 31, 2015 shares	Dec. 31, 2013 $ / shares
Stock
Convertible preferred stock, shares outstanding | shares	31,397,000		31,397,221
Common stock, shares authorized | shares	82,000,000	750,000,000
Preferred stock, shares authorized | shares	50,000,000	50,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Liquidation Amount	$ 133,757
Proceeds, net of Issuance Costs	240,612
Minimum IPO price for automatic conversion	$ 40,000
Minimum holder consenting to automatic conversion (as a percent)	70.00%
Maximum recapitalization for automatic conversion	$ 100,000
Convertible preferred stock
Stock
Convertible preferred stock, shares outstanding | shares	31,397,000
Preferred stock, shares authorized | shares	51,233,000
Liquidation Amount	$ 133,757
Proceeds, net of Issuance Costs	$ 240,612
A-1
Stock
Convertible preferred stock, shares outstanding | shares	3,067,000
Preferred stock, shares authorized | shares	5,000,000
Liquidation Amount	$ 20
Proceeds, net of Issuance Costs	$ 20
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 0.0065
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 0.0065
Dividend rate (as a percent)	0.0005%
A
Stock
Convertible preferred stock, shares outstanding | shares	5,014,000
Preferred stock, shares authorized | shares	8,173,000
Liquidation Amount	$ 4,005
Proceeds, net of Issuance Costs	$ 3,927
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 0.7987
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 0.7987
Dividend rate (as a percent)	0.0639%
B
Stock
Convertible preferred stock, shares outstanding | shares	3,491,000
Preferred stock, shares authorized | shares	5,745,000
Liquidation Amount	$ 6,600
Proceeds, net of Issuance Costs	$ 6,569
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 1.8908
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 1.8908
Dividend rate (as a percent)	0.1513%
C
Stock
Convertible preferred stock, shares outstanding | shares	5,485,000
Preferred stock, shares authorized | shares	8,941,000
Liquidation Amount	$ 12,160
Proceeds, net of Issuance Costs	$ 58,876
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 2.2168
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 2.2168
Number of directors electable | director	1
Number of directors elected | director	0
Dividend rate (as a percent)	0.1773%
D
Stock
Convertible preferred stock, shares outstanding | shares	4,107,000
Preferred stock, shares authorized | shares	6,694,000
Liquidation Amount	$ 20,047
Proceeds, net of Issuance Costs	$ 80,788
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 4.8819
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 4.8819
Dividend rate (as a percent)	0.3911%
E
Stock
Convertible preferred stock, shares outstanding | shares	5,884,000
Preferred stock, shares authorized | shares	9,592,000
Liquidation Amount	$ 35,425
Proceeds, net of Issuance Costs	$ 35,019
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 6.0199			$ 6.02
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 6.0199
Dividend rate (as a percent)	0.4817%
F
Stock
Convertible preferred stock, shares outstanding | shares	4,349,000
Preferred stock, shares authorized | shares	7,088,000
Liquidation Amount	$ 55,500
Proceeds, net of Issuance Costs	$ 55,413
Convertible preferred stock conversion numerator (in dollars per share) | $ / shares	$ 12.7629
Convertible preferred stock conversion denominator (in dollars per share) | $ / shares	$ 12.7629
Dividend rate (as a percent)	1.021%
A and B
Stock
Number of directors electable | director	2