Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:
State	$ 63,000	$ 7,000	$ 3,000
Total current provision	63,000	7,000	3,000
Deferred:
Federal	540,000	504,000	(318,000)
State	37,000	68,000	(291,000)
Total deferred (benefit) provision	577,000	572,000	(609,000)
Total income tax (benefit) provision	640,000	579,000	(606,000)
Tax benefit associated with a beneficial conversion feature on its convertible notes payable			1,100,000
U.S. federal statutory tax rate (as a percent)	34.00%	34.00%	34.00%
Reconciliation between the amount computed by applying the U.S. federal statutory tax rate of 34% to income before income taxes and the income tax (benefit) provision
Income tax benefit based on the federal statutory rate	34.00%	34.00%	34.00%
State income taxes, net of federal benefit	2.00%	(0.90%)	7.60%
Nondeductible expenses	(0.70%)	(1.50%)	(0.10%)
Change in valuation allowance	(34.70%)	(26.30%)	(40.00%)
Stock-based compensation	(2.00%)	(8.30%)	(0.90%)
Other	0.10%	0.60%	0.20%
Effective Income Tax Rate Reconciliation, Percent, Total	(1.30%)	(2.40%)	0.80%
Deferred income tax assets:
Net operating loss carryforwards	56,957,000	49,921,000
Stock-based compensation	18,648,000	8,262,000
Accrued expenses	1,932,000	2,852,000
Research and development tax credits	610,000	610,000
Other	277,000	172,000
Gross deferred tax assets	78,424,000	61,817,000
Valuation allowance	(64,449,000)	(47,858,000)	(41,412,000)	(11,348,000)
Net deferred tax assets	13,975,000	13,959,000
Deferred tax liabilities:
State taxes	(3,802,000)	(3,296,000)
Property, equipment and software	(3,985,000)	(3,353,000)
Intangible assets and goodwill	(8,020,000)	(8,566,000)
Gross deferred tax liabilities	(15,807,000)	(15,215,000)
Total net deferred tax liabilities	$ (1,832,000)	$ (1,256,000)