Stock-Based Compensation (Details 2) (USD $)	12 Months Ended		0 Months Ended	12 Months Ended	0 Months Ended		1 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended		33 Months Ended	12 Months Ended						9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended					0 Months Ended	3 Months Ended				0 Months Ended
	Dec. 31, 2013	Dec. 31, 2013 Service based restricted stock units 2012 Plan	Dec. 05, 2012 Service based restricted stock units CEO	Dec. 31, 2013 Performance based restricted stock units	Mar. 20, 2013 Performance based restricted stock units CEO	Dec. 05, 2012 Performance based restricted stock units CEO	Dec. 31, 2013 Performance based restricted stock units CEO	Dec. 31, 2013 Founder	Dec. 31, 2012 Founder	Dec. 31, 2011 Stock options	Dec. 31, 2013 Stock options	Dec. 31, 2012 Stock options	Dec. 31, 2013 Stock options	Dec. 31, 2013 Stock options Minimum	Dec. 31, 2012 Stock options Minimum	Dec. 31, 2011 Stock options Minimum	Dec. 31, 2013 Stock options Maximum	Dec. 31, 2012 Stock options Maximum	Dec. 31, 2011 Stock options Maximum	Dec. 31, 2011 Stock options Employees	Dec. 31, 2013 Stock options Employees	Dec. 31, 2012 Stock options Employees	Dec. 31, 2011 Stock options Non-employees	Dec. 31, 2013 Stock options Non-employees	Dec. 31, 2012 Stock options Non-employees	Dec. 31, 2011 Stock options Non-employees	Dec. 31, 2013 Restricted stock units	Dec. 31, 2012 Restricted stock units	Dec. 05, 2012 Restricted stock units CEO	Dec. 31, 2013 Restricted stock units CEO	Sep. 30, 2013 Restricted stock units CEO	Jun. 30, 2013 Restricted stock units CEO	Mar. 31, 2013 Restricted stock units CEO	Feb. 07, 2014 Restricted stock units Performance based restricted stock units
Shares
Unvested at the beginning of the period (in shares)								1,645,141	2,319,646
Granted (in shares)			128,205			64,103	32,051																						192,308
Vested (in shares)							(19,230)	(658,060)	(674,505)																					(16,025)	(16,025)	(16,025)	(16,025)
Unvested at the end of the period (in shares)								987,081	1,645,141
Shares
Outstanding at the beginning of the period (in shares)											1,218,153
Granted (in shares)											1,537,172										1,537,172	679,251			39,685	165,339
Exercised (in shares)											(42,799)
Forfeited (in shares)											(278,158)
Cancelled (in shares)											(21,131)
Outstanding at the end of the period (in shares)											2,413,237	1,218,153	2,413,237
Exercisable at the end of the period (in shares)											468,710		468,710
Vested and expected to vest at the end of the period (in shares)											1,445,760		1,445,760
Weighted average exercise price per share
Outstanding at the beginning of the period (in dollars per share)											$ 3.83
Granted (in dollars per share)											$ 12.87										$ 12.87	$ 6.59			$ 4.81	$ 0.04
Exercised (in dollars per share)											$ 0.99
Forfeited (in dollars per share)											$ 7.07
Cancelled (in dollars per share)											$ 4.01
Outstanding at the end of period (in dollars per share)											$ 9.26	$ 3.83	$ 9.26
Exercisable at the end of the period (in dollars per share)											$ 3.46		$ 3.46
Vested and expected to vest at the end of the period (in dollars per share)											$ 8.14		$ 8.14
Weighted average remaining contractual term
Outstanding at the beginning of the period											9 years 18 days	9 years 4 months 2 days
Outstanding at the end of the period											9 years 18 days	9 years 4 months 2 days
Exercisable at the end of the period											8 years 3 months 11 days
Vested and expected to vest at the end of the period											8 years 10 months 24 days
Aggregate intrinsic value
Outstanding at the beginning of the period											$ 5,535,000
Outstanding at the end of period											6,087,000	5,535,000	6,087,000
Exercisable at the end of period											3,112,000		3,112,000
Vested and expected to vest at the end of the period											4,192,000		4,192,000
Total intrinsic value										0	400,000	48,000	400,000
Development stage product development revenues	0
Assumptions used to estimate fair value of each stock-based option award on the grant date using the Black-Scholes option pricing model
Risk free interest rate (as a percent)														0.91%	0.80%	1.20%	2.11%	1.78%	1.84%
Volatility (as a percent)														83.00%	79.00%	79.00%	91.00%	89.00%	82.00%
Expected term														5 years 1 month 6 days	5 years 1 month 6 days	6 years	9 years 11 months 5 days	9 years 11 months 5 days	9 years 9 months
Additional disclosures
Weighted average grant-date fair value of options granted (in dollars per share)																					$ 9.34	$ 4.82												$ 8.75
Granted (in dollars per share)			$ 7.80		$ 10.00
Vested in period fair value																											800,000
Share-based compensation expense				0																26,000	2,300,000	300,000	300,000	2,200,000	1,000,000		700,000	36,000
Total unrecognized compensation cost, net of estimated forfeitures, related to unvested stock options and restricted stock units (in dollars)	$ 8,800,000	$ 500,000
Weighted average period for recognition of compensation cost related to unvested stock awards	2 years 8 months 12 days	1 year