Income Taxes - Reconciliation to the Federal Statutory Rate (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	34.00%	34.00%	34.00%
State, net of federal benefit	(61.80%)	0.90%	(0.10%)
Stock compensation	1.70%	0.00%	0.30%
Research and development credit	287.80%	0.00%	6.50%
Return to provision and true-ups	(3.90%)	0.00%	(2.80%)
Change in valuation allowance	(249.30%)	(35.90%)	(12.70%)
Other	(8.50%)	1.30%	(0.40%)
Effective income tax rate	0.00%	0.30%	24.80%