Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Cash, Cash Equivalents and Investments [Table Text Block]

Cash and cash equivalents and short-term investments consist of the following:

	Amortized Cost				Fair Value
	December 31,		Unrealized		December 31,
Description	2016		(Losses) Gains		2016
Cash and cash equivalents:
Cash and money market funds	$	12,125,898	$	-	$	12,125,898
Government-sponsored enterprise securities (original maturities within three months)		141,869,024		-		141,869,024
Total cash and cash equivalents	$	153,994,922	$	-	$	153,994,922
Short-term investments:
U.S. Treasury securities	$	20,018,323	$	(1,273)	$	20,017,050
Government-sponsored enterprise securities (original maturities within six months)		46,793,691		221		46,793,912
Total short-term investments	$	66,812,014	$	(1,052)	$	66,810,962
Total cash, cash equivalents and short-term investments	$	220,806,936	$	(1,052)	$	220,805,884

Property And Equipment Estimated Useful Lives [Table Text Block]

Property and equipment are depreciated using the straight-line method over the estimated useful lives of the respective assets as follows:

Asset Category		Estimated Useful Life (in Years)

Leasehold improvements		8-10
Furniture and office equipment		5
Computer and other equipment		3-5

Schedule of Restructuring Reserve by Type of Cost [Table Text Block]

The remaining accrued liability relating to our restructuring expense as of December 31, 2016 is as follows:

	Balance as of						Balance as of
	December 31,		Paid		Amortized		December 31,
Description	2015		2016		2016		2016

Accrued severance expense	$	131,822	$	131,822	$	-	$	-
Accrued sublease expense		358,769		-		249,643		109,126
Total accrued restructuring expense	$	490,591	$	131,822	$	249,643	$	109,126

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

Share-based compensation expense for 2016, 2015 and 2014 is as follows:

	Year Ended December 31,
	2016		2015		2014

Research and development	$	146,489	$	122,412	$	452,870
General and administrative		2,093,526		544,346		1,202,777
Restructuring benefit		-		(53,741)		-
Total share-based compensation expense	$	2,240,015	$	613,017	$	1,655,647

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

A reconciliation of the numerators and denominators of the basic and diluted per share computations for the year ended December 31, 2016 is as follows (a reconciliation is not required for the years ended December 31, 2015 and 2014 since the Company recorded a net loss for those years):

	Year Ended
	December 31, 2016

Numerator

Net income	$	193,854,173
Net income allocated to participating securities		-
Numerator for basic income per share		193,854,173
Incremental allocation of net income to participating securities		-
Change in fair value of dilutive warrants		-
Numerator for diluted income per share	$	193,854,173

Denominator

Weighted-average outstanding common shares for basic income per share		65,306,962
Dilutive effect of stock options		350,840
Dilutive effect of warrants		-
Denominator for diluted income per share		65,657,802