Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Royalties	$ 25,431,012	$ 20,800,757	$ 12,985,370
Licensing revenue	819,943	1,949,378	1,059,254
Total revenues	26,250,955	22,750,135	14,044,624
Costs and expenses:
Research and development	1,327,923	1,034,288	1,263,512
General and administrative	7,896,616	7,272,532	5,814,185
Total costs and expenses	9,224,539	8,306,820	7,077,697
Operating income	17,026,416	14,443,315	6,966,927
Other income:
Interest income	295,783	92,926	32,158
Other	52,805	14,719	33,582
Total other income	348,588	107,645	65,740
Income before income tax	17,375,004	14,550,960	7,032,667
Income tax provision	(6,002,765)	(4,933,328)	(2,386,707)
Net income	$ 11,372,239	$ 9,617,632	$ 4,645,960
Earnings per common share:
Basic (in dollars per share)	$ 1.61	$ 1.41	$ 0.72
Diluted (in dollars per share)	$ 1.56	$ 1.32	$ 0.66
Shares used in calculation of net income per common share:
Basic (in shares)	7,061,404	6,827,355	6,477,457
Diluted (in shares)	7,283,262	7,272,989	7,079,570