Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (27,471,094)	$ (14,325,484)	$ (11,810,938)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss (gain) on disposal of fixed assets	4,562	(24,845)	22,941
Depreciation and amortization	378,711	234,813	130,520
Stock-based compensation expense	3,946,027	2,070,194	1,979,364
Amortization of debt costs	346,157	248,799
Accretion of discount on debt	88,123	57,117
Change in fair value of financial instruments	726,421	(1,425,850)	1,084,114
Stock and warrant issued in connection with consulting services	0	0	198,791
Changes in operating assets and liabilities:
Decrease (increase) in other assets	(37,296)	(258)	25,631
Decrease (increase) in accounts receivable	(42,042)	22,300	89,387
Increase in prepaid expenses	(420,026)	(216,470)	(92,748)
Increase in accounts payable and accrued expenses	361,432	632,299	1,055,690
Net cash used in operating activities	(22,119,025)	(12,727,385)	(7,317,248)
Investing activities:
Capital expenditures	(2,241,066)	(363,290)	(649,784)
Proceeds from disposals of capital equipment	7,600	63,500	500
Net cash used in investing activities	(2,233,466)	(299,790)	(649,284)
Financing activities
Proceeds from sale of common stock, net of expenses	61,215,399	0	18,829,644
Proceeds from exercise of warrants	1,389,427	0	3,599,831
Proceeds from exercise of options	860,852	0	38,249
Borrowings under equipment line of credit	1,086,062	0	515,964
Repayments under equipment line of credit	0	(515,964)	0
Borrowings under debt agreement	0	15,000,000	0
Net cash provided by financing activities	64,551,740	14,484,036	22,983,688
Net change in cash and cash equivalents	40,199,249	1,456,861	15,017,156
Cash and cash equivalents—Beginning of period	27,293,798	25,836,937	10,819,781
Cash and cash equivalents—End of period	67,493,047	27,293,798	25,836,937
Supplementary disclosure of cash flow activity:
Cash paid for taxes	16,934	2,400	7,650
Cash paid for interest	1,061,993	425,256	9,459
Supplemental disclosure of non-cash investing and financing activities:
Warrants issued in connection with Loan and Security Agreement	0	235,857	0
Reclassification of derivative financial instruments to additional paid-in capital	435,365	0	(5,417,871)
Preferred stock dividends accrued	$ 24,240	$ 23,015	$ 29,840