Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	[1]	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 3,978,604		$ 3,344,753
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	699,703		545,067
Stock-based compensation expense	32,512		33,476
Deferred tax expense	0		97,508
Changes in operating assets and liabilities:
Accounts receivable	(6,955,839)		(1,117,501)
Income tax receivable	1,067,002		212,174
Prepaid expenses and other current assets	42,582		40,709
Patent costs	(44,598)		0
Accounts payable and accrued expenses	308,152		422,793
Deferred revenue	(4,409)		(259,713)
Net cash (used in) provided by operating activities	(876,291)		3,319,266
Cash flows from investing activities:
Maturity of marketable investments	20,287,000		18,217,000
Purchases of marketable investments	(14,318,018)		(17,304,251)
Net cash provided by investing activities	5,968,982		912,749
Cash flows from financing activities:
Proceeds from stock option exercises	132,400		258,250
Payments for repurchase of common stock	0		(221,821)
Net cash provided by financing activities	132,400		36,429
Increase in cash and cash equivalents	5,225,091		4,268,444
Cash and cash equivalents at beginning of year	7,333,810		4,763,364
Cash and cash equivalents at end of period	12,558,901		9,031,808
Cash paid during the period for:
Interest	0		0
Taxes	$ 0		$ 1,460,000

[1] As of January 1, 2018, the Company adopted the requirements of ASC 606 using the modified retrospective adoption method, and as a result, there is a lack of comparability of certain amounts to the prior periods presented. See Note 2 for additional discussion.