Term Loans (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended			6 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012	Mar. 31, 2013 GECC Term Loan	Dec. 31, 2013 GECC Term Loan	Dec. 31, 2012 GECC Term Loan	Dec. 31, 2011 GECC Term Loan	Jan. 31, 2014 GECC Term Loan Subsequent event payment	Dec. 31, 2013 GECC Term Loan Maximum	Dec. 31, 2012 Oxford Term Loan payment	May 31, 2011 Oxford Term Loan payment	Mar. 31, 2011 Oxford Term Loan	Jun. 30, 2013 Oxford Term Loan	Dec. 31, 2013 Oxford Term Loan	Dec. 31, 2012 Oxford Term Loan	Dec. 31, 2011 Oxford Term Loan	Dec. 31, 2012 Oxford Term Loan Maximum	Dec. 31, 2013 Oxford Term Loan Minimum
Term Loans
Proceeds from term loans	$ 13,500,000	$ 2,000,000		$ 12,900,000								$ 2,000,000
Principal balance	23,271,000			22,500,000
Annual interest rate on term loan (as a percent)					9.75%							13.35%
Number of equal monthly payments of principal plus accrued interest								30			36
Exit fee to be paid					788,000
Interest expense recognized					2,500,000	1,700,000	1,800,000							127,000	172,000	192,000
Transaction and exit fees and expenses recognized in interest expense					566,000	321,000	275,000
Amount of equipment financing allowed under covenants without any restriction									4,000,000
Amount of debt assumption from acquisitions requiring prior written consent under covenants																		2,000,000
Additional amount that the Company may fully utilized in equipment financing																	600,000
Principal amount of debt issued													600,000
Number of equal monthly payments of principal plus accrued interest										36
Legal fees and expenses paid														108,000
Future principal payments under the GECC and Oxford Term Loans
2014	9,451,000
2015	9,214,000
2016	4,606,000
Total principal payments	23,271,000			22,500,000
Less current portion	(9,451,000)		(7,924,000)
Long term obligation	$ 13,820,000		$ 4,464,000