Term Loan (Details) (USD $)		1 Months Ended		3 Months Ended		6 Months Ended					1 Months Ended
	Jun. 30, 2012	Mar. 31, 2012 Term Loan	Sep. 30, 2011 Term Loan	Jun. 30, 2012 Term Loan	Jun. 30, 2011 Term Loan	Jun. 30, 2012 Term Loan Item	Jun. 30, 2011 Term Loan	Dec. 31, 2011 Term Loan	Mar. 31, 2011 Term Loan	Jun. 30, 2012 Term Loan Minimum	Dec. 31, 2010 Term Loan MidCap	Mar. 31, 2011 Term Loan GECC
Term Loan
Amount borrowed											$ 10,000,000	$ 5,000,000
Amount owed under the term loan	13,900,000								15,000,000
Basis of interest rate						LIBOR
Interest rate margin (as a percent)				6.25%		6.25%
Fixed annual interest rate (as a percent)										9.50%
Extension of interest-only period			6 months
Upfront fee due upon amendment of the Term loan		25,000
Additional Final Payment Fee due upon repayment of the Term Loan in full.		37,500
Number of equal consecutive monthly installments						34
Rate of prepayment premium in year three (as a percent)						1.00%
Rate of prepayment premium in year two (as a percent)						2.00%
Original Payment Fee payable upon repayment of term loan in full						500,000
Capitalized deferred financing costs				100,000		100,000		200,000
Interest expense on the term loan				$ 400,000	$ 400,000	$ 800,000	$ 700,000