Notes Payable (Details) (USD $)		1 Months Ended		1 Months Ended		3 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended					1 Months Ended
	Mar. 31, 2014	Sep. 30, 2012 Loan and Security Agreement Tranche	Mar. 31, 2014 Loan and Security Agreement	Sep. 30, 2012 Loan and Security Agreement LIBOR variable interest rate	Sep. 30, 2012 Loan and Security Agreement Prepayment through December 31, 2014	Mar. 31, 2014 Loan and Security Agreement Prepayment through December 31, 2014	Sep. 30, 2012 Loan and Security Agreement Prepayment in 2015	Mar. 31, 2014 Loan and Security Agreement Prepayment in 2015	Sep. 30, 2012 Loan and Security Agreement Prepayment in final year	Mar. 31, 2014 Loan and Security Agreement Prepayment in final year	Sep. 30, 2012 Loan and Security Agreement Minimum	Sep. 30, 2012 Loan and Security Agreement First Tranche, issued in September 2012	Sep. 30, 2012 Loan and Security Agreement First Tranche, issued in September 2012 Series E Convertible Preferred Stock	Sep. 30, 2012 Loan and Security Agreement Second Tranche, issued in December 2012	Jun. 30, 2013 Loan and Security Agreement Final tranche that may be drawn at option of Company no later than June 2013	Sep. 30, 2012 Loan and Security Agreement Final tranche that may be drawn at option of Company no later than June 2013
Notes payable
Maximum amount of borrowing under the agreement		$ 15,000,000										$ 5,000,000		$ 5,000,000		$ 5,000,000
Amount of borrowing required to be drawn											10,000,000
Amount of remaining borrowing capacity		5,000,000
Number of loan tranches		3
Variable rate basis				one month LIBOR
Spread on variable rate (as a percent)				6.00%
LIBOR floor rate				3.00%
Straight-line principal payments period		36 months
Percentage of exit fee of drawn amount		3.00%
Warrants issued as a percentage of amount drawn under credit facility													4.00%
Exercise price of warrant (in dollars per share)	$ 5.13												$ 12.11		$ 12.11
Prepayment fee percentage						5.00%		2.00%		1.00%
Prepayment period start date							Jan. 01, 2014		Jan. 01, 2016
Prepayment period end date					Dec. 31, 2014		Dec. 31, 2015
Tranche draw down															5,000,000
Debt discount related to issuance of warrants			98,000
Issuance of warrant to purchase shares of common stock	38,997														49,548
Warrants initial fair value															$ 130,000