Debt Obligations - Additional Information (Details) (USD $)	0 Months Ended	12 Months Ended
	Jun. 06, 2014	Dec. 31, 2014	Jan. 31, 2011 trust related_party	Jun. 30, 2011
Debt Instrument [Line Items]
Number of trusts related to two co-founders			2
Number of related co-founders			2
Prepay notice period		10 days
Repayment of notes payable and accrued interest	$ 23,600,000
Withholding taxes	1,100,000
Converted debt amount	96,500,000
Convertible notes
Debt Instrument [Line Items]
Interest rate		6.00%
Minimum amount of indebtedness not subject to acceleration of maturity after failure to make other payment obligations		10,000,000
Convertible notes | Convertible notes issued January 2011
Debt Instrument [Line Items]
Aggregate principal amount			55,000,000
Convertible notes | Convertible debt issued June 2011
Debt Instrument [Line Items]
Aggregate principal amount				20,000,000
Trusts related to two co-founders | Convertible notes | Related party convertible notes issued January 2011
Debt Instrument [Line Items]
Aggregate principal amount			25,000,000
Common Stock | Convertible notes payable
Debt Instrument [Line Items]
Shares issued upon conversion (in shares)		1,543,000
Common Stock
Debt Instrument [Line Items]
Issue price (in dollars per share)	$ 43
Shares issued upon conversion (in shares)	24,000,000
Common Stock | Convertible notes payable
Debt Instrument [Line Items]
Shares issued upon conversion (in shares)	2,200,000