Common Shares Reserved for Issuance - Narrative (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2013 shares	Dec. 31, 2015 vote_per_share $ / shares shares	Dec. 31, 2013 shares	Dec. 31, 2014 $ / shares shares
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)		0		0
Convertible preferred stock, shares authorized after IPO (in shares)		100,000,000		100,000,000
Convertible preferred stock, shares issued (in shares)		0		0
Common stock, shares authorized (in shares)		1,000,000,000		1,000,000,000
Common stock, par value (usd per share) | $ / shares		$ 0.0001		$ 0.0001
Voting right per common share | vote_per_share		1
Convertible preferred stock
Class of Stock [Line Items]
Shares issued from conversion of preferred stock and warrants (shares)	74,221,553		(64,590,000)
Series A
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	11,164,000
Series B
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	10,985,000
Series C
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	7,049,000
Series D
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	26,231,000
Series E
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	4,412,000
Series F
Class of Stock [Line Items]
Convertible preferred stock, shares outstanding (in shares)	4,274,000