Consolidated Statements of Cash Flows (unaudited) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 3,560,045	$ 1,880,119
Adjustments to reconcile net income to net cash provided By operating activities:
Depreciation and amortization	48,242	43,529
Stock-based compensation expense	106,621	202,085
Deferred tax assets	424	619,410
Changes in operating assets and liabilities:
Accounts receivable	37,678	31,523
Prepaid expenses and other current assets	(294,715)	110,655
Accounts payable and accrued expenses	86,204	15,607
Deferred revenue	(116,242)	(327,824)
Net cash provided by operating activities	3,428,257	2,575,104
Cash flows from investing activities:
Maturity of marketable investments	7,790,000	5,000,000
Purchases of marketable investments	(9,396,964)	(5,190,000)
Payment for royalty buy down	0	(1,500,000)
Net cash used in investing activities	(1,606,964)	(1,690,000)
Cash flows from financing activities:
Proceeds from stock option exercises	10,000	148,425
Payments for repurchase of common stock	(608,052)	(674,501)
Excess tax benefits from share-based payment arrangements	0	268,001
Net cash used in financing activities	(598,052)	(258,075)
Increase in cash and cash equivalents	1,223,241	627,029
Cash and cash equivalents at beginning of year	3,383,737	3,196,831
Cash and cash equivalents at end of period	4,606,978	3,823,860
Cash paid during the year for:
Interest	0	0
Taxes	$ 1,778,500	$ 162,000