CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss)	Retained Earnings [Member]	Total
Balance at beginning of period at Dec. 31, 2014			$ (143,928)
Net loss					$ (31,475,655)
Unrealized loss on foreign currency translation					(1,158)
Unrealized loss on securities					168,487
Balance at end of period at Sep. 30, 2015			23,401
Balance at beginning of period at Dec. 31, 2014			(143,928)
Balance at end of period at Dec. 31, 2015	$ 42,035	$ 381,118,489	(79,399)	$ (209,734,988)	171,346,137
Balances (in shares) at Dec. 31, 2015	42,034,733
Balance at beginning of period at Jun. 30, 2015			(28,141)
Net loss					(10,001,708)
Unrealized loss on foreign currency translation					123
Unrealized loss on securities					51,419
Balance at end of period at Sep. 30, 2015			23,401
Balance at beginning of period at Dec. 31, 2015	$ 42,035	381,118,489	(79,399)	(209,734,988)	171,346,137
Exercise of stock options	$ 66	129,240			129,306
Exercise of stock options (in shares)	66,888
Stock-based compensation	$ 122	7,731,594			7,731,716
Stock-based compensation (in shares)	121,812
Employee stock purchase plan	$ 45	137,880			137,925
Number of shares purchased under ESPP	44,636
Net loss				(32,822,796)	(32,822,796)
Unrealized loss on securities			111,039		111,039
Balance at end of period at Sep. 30, 2016	$ 42,268	389,117,203	31,640	(242,557,784)	$ 146,633,327
Balances (in shares) at Sep. 30, 2016	42,268,069
Balance at beginning of period at Jun. 30, 2016			96,246
Exercise of stock options (in shares)					10,471
Net loss					$ (8,707,396)
Unrealized loss on securities					(64,606)
Balance at end of period at Sep. 30, 2016	$ 42,268	$ 389,117,203	$ 31,640	$ (242,557,784)	$ 146,633,327
Balances (in shares) at Sep. 30, 2016	42,268,069