Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 9,617,632	$ 4,645,960	$ 5,285,847
Adjustments to reconcile net income to net cash provided in operating activities:
Amortization	933,009	247,097	64,323
Stock-based compensation expense	105,782	21,416	111,636
Deferred tax expense	455,799	429,005	(10,653)
Gain on the sale of fixed assets	0	(1,150)	0
Changes in operating assets and liabilities:
Accounts receivable	390,811	2,051,335	77,942
Income tax receivable	(263,727)	(397,408)	(204,638)
Prepaid expenses and other current assets	(124,647)	81,708	(176,795)
Patent costs	(25,934)	(198,952)	0
Accounts payable and accrued expenses	67,313	(90,580)	121,411
Deferred royalty buy-down	(600,000)	(600,000)	(600,000)
Deferred revenue	50,622	(59,255)	(133,524)
Net cash provided by operating activities from operations	10,606,660	6,129,176	4,535,549
Cash flows from investing activities:
Maturities of marketable securities	14,070,544	7,646,964	9,710,000
Purchases of marketable securities	(34,180,085)	(12,848,374)	(11,556,964)
Proceeds from sale of fixed assets	0	1,150	0
Net cash used in investing activities from operations	(20,109,541)	(5,200,260)	(1,846,964)
Cash flows from financing activities:
Proceeds from stock option exercises	2,823,983	2,146,821	30,000
Repurchases of common stock	(1,802,466)	(829,613)	(674,874)
Excess tax benefits from share-based payment arrangements	3,808,423	1,939,832	197,412
Net cash provided by (used in) financing activities from operations	4,829,940	3,257,040	(447,462)
(Decrease) increase in cash and cash equivalents	(4,672,941)	4,185,956	2,241,123
Cash and cash equivalents at beginning of year	9,810,816	5,624,860	3,383,737
Cash and cash equivalents at end of year	5,137,875	9,810,816	5,624,860
Cash paid during the year for:
Interest	0	0	0
Taxes	$ 1,906,000	$ 415,279	$ 2,713,500