Consolidated Statements of Cash Flows (USD $)	12 Months Ended			124 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Cash flows from operating activities:
Net loss	$ (43,643,071)	$ (12,737,654)	$ (15,087,223)	$ (118,183,350)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Impairment of bonds	0	0	0	151,402
Loss from sale of assets	0	217,296	0	217,296
Depreciation	201,323	410,601	479,500	2,366,669
Foreign currency loss on liquidation	191,733	0	0	191,733
Stock-based compensation	3,348,989	1,865,755	1,692,885	9,777,870
Amortization of investment premium	118,180	0	0	118,180
Revaluation of warrants	24,625,598	(1,044,826)	(672,476)	23,075,576
Changes in:
Prepaid expenses and other current assets	(387,690)	(630,422)	53,467	(1,359,620)
Accounts payable, accrued expenses, and other current liabilities	2,241,575	(83,234)	(123,976)	3,745,777
Deferred revenue	(2,446,105)	14,608,270	0	12,162,165
Interest accrued on promissory notes	0	0	0	91,249
Net cash (used in) provided by operating activities	(15,749,468)	2,605,786	(13,657,823)	(67,645,053)
Cash flows from investing activities:
Redemptions of (investments in) certificates of deposit	3,328	(3,227)	86,922	(627,631)
Purchases of investment securities	(65,940,976)	0	0	(65,940,976)
Sales of investment securities	1,119,075	0	0	1,119,075
Purchases of equipment, improvements, and furniture and fixtures	(38,795)	(62,817)	(29,063)	(1,397,238)
Net cash provided by (used in) investing activities	(64,857,368)	(66,044)	57,859	(66,846,770)
Cash flows from financing activities:
Proceeds from issuance of stock offerings, net of issuance costs	108,499,996	0	19,690,079	172,477,162
Proceeds from issuance of common stock warrants	0	0	5,198,217	7,385,897
Payments of capital lease obligation	(81,762)	(249,667)	(270,206)	(1,335,567)
Proceeds from exercise of options	0	0	0	42,705
Proceeds from exercise of warrants	0	0	0	375,000
Proceeds from issuance of convertible promissory notes payable	0	0	0	1,250,000
Net cash provided by (used in) financing activities	108,418,234	(249,667)	24,618,090	180,195,197
Effect of exchange rate changes	(7,233)	(6,345)	(29,099)	(191,733)
Net increase (decrease) in cash and cash equivalents	27,804,165	2,283,730	10,989,027	45,511,641
Cash and cash equivalents - beginning of period	17,707,476	15,423,746	4,434,719	0
Cash and cash equivalents - end of period	45,511,641	17,707,476	15,423,746	45,511,641
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	4,234	13,478	25,108	181,980
Supplemental disclosures of noncash activities:
Conversion of promissory note payable, including accrued interest of $91,250 into common shares	0	0	0	1,341,249
Issuance of 108,169 warrants for private placement agent fees	0	0	0	1,471,485
Acquisition of equipment pursuant to capital leases	0	0	0	1,335,567
Issuance of common stock for cashless warrant exchange	$ 1,018,215	$ 0	$ 0	$ 1,018,215