Summary of Significant Accounting Policies - Schedule of Assumptions Used in Valuation of Redeemable Convertible Preferred Stock Warrants (Details) - Redeemable Convertible Preferred Stock Warrants - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements
Exercise price	$ 26.00	$ 26.00	$ 26.00
Minimum
Fair Value Measurements
Expected volatility	42.40%	43.60%	52.80%
Risk-free interest rate	1.22%	1.76%	1.81%
Expected term (in years)	4 years	5 years	6 years
Maximum
Fair Value Measurements
Expected volatility	52.00%	52.90%	53.80%
Risk-free interest rate	1.86%	2.27%	2.17%
Expected term (in years)	9 years	10 years	10 years