CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net loss	$ (26,446,390)	$ (35,451,987)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	104,030	139,691
Stock-based compensation expense	1,463,647	4,325,575
Change in fair value of derivative liabilities	(96,642)	(2,073,581)
Change in fair value of contingent consideration	3,326,000	3,252,000
Non-cash interest expense	2,530,254	2,129,286
Debt exchange expense		818,541
Unrealized foreign currency loss		89,660
Loss on sale of equipment	153,572
Impairment charge	5,169,000
Deferred income tax benefit	(2,317,000)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	1,130,944	628,751
Accounts payable, accrued expenses and other liabilities	294,100	445,460
Net cash used in operating activities	(14,688,485)	(25,696,604)
Cash flows from investing activities
Purchase of property and equipment		(76,666)
Proceeds from sale of equipment	152,756
Purchase of short-term investments		(19,292,969)
Sales and maturities of short-term investments	5,107,598	46,299,020
Net cash provided by investing activities	5,260,354	26,929,385
Cash flows from financing activities
Proceeds from exercise of stock options and warrants		31,201
Retirement of convertible notes payable		(825,001)
Proceeds from issuance of common stock, net		2,583,889
Net cash used in financing activities		1,790,089
Effect of exchange rate changes on cash and cash equivalents	11,223	(186,256)
Net increase (decrease) in cash and cash equivalents	(9,416,908)	2,836,614
Cash and cash equivalents - beginning of period	15,302,382	13,073,137
Cash and cash equivalents - end of period	5,885,474	15,909,751
Noncash investing and financing activities
Conversion of convertible notes to common stock		2,080,292
Cash paid for interest	$ 1,750,000	$ 1,750,000