Income taxes: (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 subsidiary	Dec. 31, 2012	Dec. 31, 2011
Components of (loss) income before income taxes
Domestic	$ 30,779,000	$ 20,411,000	$ 27,832,000
Foreign	(23,792,000)	(23,911,000)	(22,250,000)
Income (loss) before income taxes	6,987,000	(3,500,000)	5,582,000
Current provision
State income tax	(83,000)	2,285,000	(3,432,000)
Foreign income tax	(284,000)	(344,000)	(369,000)
Deferred provision
Federal income tax	49,317,000
State Income tax	995,000	(1,245,000)	6,334,000
Foreign income tax	(243,000)	(1,447,000)	(573,000)
Income tax benefit (provision)	49,702,000	(751,000)	1,960,000
Deferred Tax Assets:
Net operating loss carry-forwards	402,484,000	385,578,000
Depreciation and amortization	3,110,000	4,187,000
Tax credits	2,775,000	2,758,000
Accrued liabilities and other	3,748,000	6,138,000
Total gross deferred tax assets	412,117,000	398,661,000
Deferred Tax Liabilities:
Convertible Notes	1,150,000	3,415,000
Equity-based compensation	248,000	600,000
Total gross deferred tax liabilities	1,398,000	4,015,000
Net deferred tax assets before valuation allowance	410,719,000	394,646,000
Valuation allowance	(354,537,000)	(388,460,000)
Net deferred tax asset	56,182,000	6,186,000
Income tax benefit due to reduction in valuation allowance	52,200,000		6,300,000
Number of subsidiaries filing income tax returns in U.S. federal, and various state and foreign jurisdictions	1
Net operating loss carry-forwards
Combined net operating loss carry-forwards	1,300,000,000
Uncertain tax positions
Liability for uncertain tax positions, including accrued interest and penalties	1,100,000	1,700,000
Expected decrease in liability for uncertain tax positions	300,000
Reconciliation of the beginning and ending amount of unrecognized tax benefits (excluding interest and penalties)
Beginning balance of unrecognized tax benefits	1,312,000	2,875,000	698,000
Gross increases-tax positions in prior periods	(51,000)	745,000	2,177,000
Decrease attributable to settlements with taxing authorities		(1,655,000)
Decrease attributable to lapses of statutes of limitation	(261,000)	(653,000)
Ending balance of unrecognized tax benefits	1,000,000	1,312,000	2,875,000
Reconciliation of the Federal statutory income taxes to the amounts reported in the financial statements
Federal income tax at statutory rates	(2,445,000)	1,225,000	(1,954,000)
State income tax, net of federal benefit	(281,000)	(387,000)	(1,368,000)
State tax credits	272,000	315,000	146,000
Foreign rate differential	255,000	227,000	1,071,000
Foreign tax expense	(122,000)	(96,000)	(342,000)
Net operating loss limitation	(238,000)	(1,081,000)
Non-deductible expenses	(464,000)	(2,551,000)	(597,000)
Change in tax reserves	503,000	1,552,000	(2,969,000)
Other	35,000	23,000	278,000
Change in valuation allowance	52,187,000	22,000	7,695,000
Income tax benefit (provision)	49,702,000	(751,000)	1,960,000
United States
Net operating loss carry-forwards
Combined net operating loss carry-forwards	395,800,000
Europe
Net operating loss carry-forwards
Combined net operating loss carry-forwards	897,900,000
Net operating loss carry-forwards not subject to expiration	727,800,000
Net operating loss carry-forwards subject to expiration	170,000,000
Mexico
Net operating loss carry-forwards
Combined net operating loss carry-forwards	1,800,000
Japan
Net operating loss carry-forwards
Combined net operating loss carry-forwards	$ 100,000