Statements of Changes in Stockholders' Equity (Deficit) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Deficit Accumulated [Member]	Total
Balance at Dec. 31, 2016	$ 9,756	$ 190,341,769	$ (101,074,968)	$ 89,276,557
Balance (in shares) at Dec. 31, 2016	28,918,516
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation expense	$ 0	6,182,841	0	6,182,841
Issuance of common stock, net of issuance costs	$ 594	17,382,349	0	17,382,943
Issuance of common stock, net of issuance costs (in shares)	1,800,000
Issuance of common stock from exercise of stock options	$ 12	118,176	0	118,188
Issuance of common stock from exercise of stock options (in shares)	35,366
Issuance of common stock from exercise of warrants	$ 31	53,118	0	53,149
Issuance of common stock from exercise of warrants (in shares)	94,200
Issuance of common stock from 401K match	$ 7	217,529	0	217,536
Issuance of common stock from 401K match (in shares)	21,123
Net loss	$ 0	0	(50,859,803)	(50,859,803)
Balance at Dec. 31, 2017	$ 10,400	214,309,370	(151,948,359)	62,371,411
Balance (in shares) at Dec. 31, 2017	30,869,205
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect of new share-based compensation guidance | ASU 2016 - 09 [Member]	$ 0	13,588	(13,588)	0
Stock based compensation expense	0	7,469,441	0	7,469,441
Issuance of common stock from exercise of stock options	$ 65	721,130	0	721,195
Issuance of common stock from exercise of stock options (in shares)	198,300
Issuance of common stock from exercise of warrants	$ 58	(58)	0	0
Issuance of common stock from exercise of warrants (in shares)	175,999
Issuance of common stock from vesting of RSUs	$ 30	(30)	0	0
Issuance of common stock from vesting of RSUs (in shares)	91,432
Issuance of common stock from 401K match	$ 38	145,129	0	145,167
Issuance of common stock from 401K match (in shares)	115,053
Net loss	$ 0	0	(40,868,006)	(40,868,006)
Balance at Dec. 31, 2018	$ 10,591	$ 222,644,982	$ (192,816,365)	$ 29,839,208
Balance (in shares) at Dec. 31, 2018	31,449,989