Accounting for Shared-Based Payments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 08, 2015	Dec. 31, 2014
Shared-based payments
Total stock-based compensation expense (in dollars)	$ 5,389	$ 999	$ 7,794	$ 2,264
Employee
Shared-based payments
Total stock-based compensation expense (in dollars)	1,115	906	2,216	1,727
Nonemployee
Shared-based payments
Total stock-based compensation expense (in dollars)	4,274	$ 93	$ 5,578	$ 537
2008 Equity Compensation Incentive Plan
Shared-based payments
Number of shares reserved under the plan					30,000,000	15,000,000
Stock options
Shared-based payments
Vesting period			3 years
Contractual term			10 years
Unrecognized compensation cost related to non-vested employee stock options, net of expected forfeitures (in dollars)	$ 8,300		$ 8,300
Weighted-average remaining vesting period over which unrecognized compensation cost is to be recognized			1 year 8 months 12 days
Number of stock options which vest upon a change of control (in shares)	4,346,000		4,346,000
Weighted-average assumptions used to estimate fair value of stock option awards using the Black-Scholes option valuation model
Risk-free interest rate, minimum (as a percent)			1.46%	1.78%
Risk-free interest rate, maximum (as a percent)			2.35%	1.98%
Expected volatility (as a percent)			60.00%	60.00%
Expected term			6 years	6 years