Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows provided by (used in) operating activities
Net loss	$ (15,492,330)	$ (18,827,388)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	19,156	15,821
Share-based compensation expense	2,192,860	282,450
Issuance of common stock for services	131,538
Amortization of premiums on investment securities	144,017
Changes in operating assets and liabilities:
Accounts receivable	211,904	49,138
Prepaid expenses and other assets	(551,524)	(617,586)
Accounts payable	(2,891,185)	3,985,489
Accrued liabilities	(365,251)	2,398,611
Deferred revenue		(1,249,992)
Net cash used in operating activities	(16,600,815)	(13,963,457)
Cash flows provided by (used in) investing activities
Purchases of investments	(92,272,925)
Maturities of investments	26,994,790	1,500,000
Purchase of property and equipment	(8,324)	(33,255)
Net cash (used in) provided by investing activities	(65,286,459)	1,466,745
Cash flows provided by (used in) financing activities
Proceeds from issuance of convertible promissory notes, net		100,000
Proceeds from stock option exercises	99,103	316,827
Proceeds from stock subscriptions	109,833	109,834
Gross proceeds of public offering	116,191,285	43,841,850
Payment of costs of public offering	(748,538)	(3,445,315)
Net cash provided by financing activities	115,651,683	40,923,196
Net increase in cash and cash equivalents	33,764,409	28,426,484
Cash and cash equivalents at beginning of period	35,150,924	15,645,528
Cash and cash equivalents at end of period	68,915,333	44,072,012
Cash paid for interest	7,073	3,317
Cash paid for taxes	$ 40,557	$ 13,437