Consolidated Statements of Cash Flows (unaudited) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ (10,787,148)	$ (6,398,894)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation	94,927	127,411
Unrealized loss on short-term investments		539,781
Noncash compensation	635,005	565,981
Change in value of warrant liability	3,447,723	(1,719,756)
Changes in operating assets and liabilities:
Accounts receivable	(435,284)	1,001,603
Other current assets	(74,125)	115,161
Other long-term assets	(22,619)	(4,671)
Accounts payable	(286,377)	153,535
Deferred revenue	(219,280)
Accrued expenses	643,876	825,477
Net cash used in operating activities	(7,003,302)	(4,794,372)
Cash flows from investing activities:
Sale of short-term investments	1,315,175
Purchase of equipment	(20,054)	(81,560)
Net cash provided by (used in) investing activities	1,295,121	(81,560)
Cash flows from financing activities:
Exercise of options		1,425
Repayment of capital lease obligation	(16,974)	(4,966)
Net cash used in financing activities	(16,974)	(3,541)
Effect of exchange rate change on cash and equivalents	(157,915)	118,371
Increase (decrease) in cash and cash equivalents	(5,883,070)	(4,761,102)
Cash and cash equivalents at beginning of period	25,652,083	22,872,589
Cash and cash equivalents at end of period	19,769,013	18,111,487
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	5,861	2,646
Supplemental schedule of noncash financing activities:
Equipment acquired through lease financing		$ 221,690