Convertible Debt and Notes Payable (Details)			3 Months Ended		9 Months Ended		40 Months Ended
		Oct. 10, 2014 USD ($)	Sep. 30, 2015 USD ($) letters_of_credit	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) letters_of_credit	Sep. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	Jan. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 10, 2014 USD ($) $ / shares
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Lessee, Assets under Capital Lease			$ 100,000	$ 100,000	$ 100,000	$ 200,000
Components of short-term borrowings and other debt
Convertible debt			123,149,000		123,149,000				$ 118,475,000
Notes Payable			63,250,000		63,250,000				63,250,000
Other Note payable			355,000		355,000				0
Capital lease obligations			3,023,000		3,023,000				3,894,000
Debt, Long-term and Short-term, Combined Amount			189,777,000		189,777,000				185,619,000
Amortization of debt discount					4,674,000	3,241,000
Cash convertible note hedge transaction					0	149,500,000
Capital Lease Obligations Incurred							$ 7,600,000
Capital Leases, Income Statement, Interest Expense			100,000	100,000	100,000	200,000
Future minimum lease payments for capital lease obligations
2015			330,000		330,000
2016			1,025,000		1,025,000
2017			938,000		938,000
2018			938,000		938,000
2019			78,000		78,000
Thereafter			0		0
Subtotal			3,309,000		3,309,000
Less: Amount representing interest	[1]		(286,000)		(286,000)
Capital lease obligations			$ 3,023,000		$ 3,023,000				3,894,000
Number of Letters of Credit | letters_of_credit			7		7
Revolving Credit Facility
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			$ 25,000,000		$ 25,000,000
Line of Credit Facility, Commitment Fee Percentage					3.00%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.38%
Minimum
Components of short-term borrowings and other debt
Capital Lease Obligation, Initial Term					48 months
Capital leases, interest rate			0.60%		0.60%
Maximum
Components of short-term borrowings and other debt
Capital Lease Obligation, Initial Term					60 months
Capital leases, interest rate			6.03%		6.03%
Cash Convertible Note Economic Hedge And Warrant Transaction
Components of short-term borrowings and other debt
Cash convertible note hedge transaction						20,500,000
Treasury Stock
Components of short-term borrowings and other debt
Cash convertible note hedge transaction						300,000
Letter of Credit, San Francisco Office, Expires October 2025 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			$ 710,000		$ 710,000
Letter of Credit, NY Office, Expires February 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			1,000,000		1,000,000
Letter of Credit, Boston Office, Expires March 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			382,000		382,000
Letter of Credit, NY Office 1, Expires May 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			355,000		355,000
Letter of Credit, NY Office 2, Expires May 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			1,861,000		1,861,000
Letter of Credit, NY Office 3, Expires October 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			794,000		794,000
Letter of Credit, NY Office 4, Expires October 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			3,935,000		3,935,000
Convertible Debt
Components of short-term borrowings and other debt
Debt Instrument, Face Amount										$ 149,500,000
Interest rate										3.00%
Principal amount of notes being converted										$ 1,000
Interest on Convertible Debt, Net of Tax			1,100,000	1,100,000	3,400,000	1,100,000
Debt Instrument, Convertible, Conversion Price | $ / shares										$ 5.33
Convertible debt, unamortized discount			26,400,000		26,400,000				$ 31,000,000	$ 35,700,000
Amortization of debt discount			1,600,000	$ 1,500,000	4,700,000	$ 3,200,000
Debt Instrument, Interest Rate, Effective Percentage										8.89%
Debt Issuance Cost					3,700,000
Repayments on long-term and short-term borrowings
2015			0		0
2016			4,485,000		4,485,000
2017			4,485,000		4,485,000
2018			4,485,000		4,485,000
2019			151,743,000		151,743,000
Thereafter			0		0
Subtotal			165,198,000		165,198,000
Less: Amount representing interest	[1]		(42,049,000)		(42,049,000)
Senior Notes
Components of short-term borrowings and other debt
Notes Payable			63,250,000		63,250,000
Debt Instrument, Face Amount		$ 63,300,000
Interest rate		8.25%
Interest on Convertible Debt, Net of Tax			1,300,000		3,900,000
Debt Issuance Cost		$ 2,900,000
Repayments on long-term and short-term borrowings
2015			1,304,000		1,304,000
2016			5,218,000		5,218,000
2017			5,218,000		5,218,000
2018			5,218,000		5,218,000
2019			5,218,000		5,218,000
Thereafter			73,686,000		73,686,000
Subtotal			95,862,000		95,862,000
Less: Amount representing interest	[1]		(32,612,000)		(32,612,000)
Insurance Note
Components of short-term borrowings and other debt
Other Note payable			355,000		355,000			$ 2,000,000
Interest rate								1.33%
Monthly payment					200,000
Repayments on long-term and short-term borrowings
2015			361,000		361,000
2016			0		0
2017			0		0
2018			0		0
2019			0		0
Thereafter			0		0
Subtotal			361,000		361,000
Less: Amount representing interest	[1]		$ (6,000)		$ (6,000)
Common Stock Class A
Components of short-term borrowings and other debt
Class of Warrant, Exercise Price of Warrants or Rights | $ / shares										$ 7.18

[1] Amount necessary to reduce net minimum payments to present value calculated at the Company's implicit rate at inception. This amount also includes the unamortized discount on the convertible debt.