CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities
Net loss	$ (17,811,871)	$ (24,556,029)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	94,736	91,454
Stock-based compensation expense	1,492,360	2,913,844
Change in fair value of derivative liabilities	(73,161)	(1,642,223)
Change in fair value of contingent consideration	2,162,000	2,129,000
Non-cash interest expense	1,646,328	1,397,884
Debt exchange expense		818,541
Unrealized foreign currency loss		75,744
Loss on sale of equipment	153,572
Changes in operating assets and liabilities:
Prepaid expenses and other assets	830,452	6,076
Accounts payable, accrued expenses and other liabilities	(388,550)	746,922
Net cash used in operating activities	(11,894,134)	(18,018,787)
Cash flows from investing activities
Purchase of property and equipment		(50,474)
Proceeds from sale of equipment	152,756
Purchase of short-term investments		(9,420,731)
Sales and maturities of short-term investments	5,107,598	27,703,705
Net cash provided by investing activities	5,260,354	18,232,500
Cash flows from financing activities
Proceeds from exercise of stock options and warrants		29,553
Retirement of convertible notes payable		(825,001)
Net cash used in financing activities		(795,448)
Effect of exchange rate changes on cash and cash equivalents	7,122	(53,236)
Net decrease in cash and cash equivalents	(6,626,658)	(634,971)
Cash and cash equivalents - beginning of period	15,302,382	13,073,137
Cash and cash equivalents - end of period	8,675,724	12,438,166
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