Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	[1]	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 13,869,585		$ 8,683,675
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	1,984,577		1,632,823
Stock-based compensation expense	159,883		100,428
Deferred tax expense	128,418		298,121
Extinguishment of accrued liabilities	(78,138)		0
Changes in operating assets and liabilities:
Accounts receivable	(2,245,522)		(871,093)
Income tax receivable	(774,624)		437,781
Prepaid expenses and other current assets	(178,453)		(48,719)
Patent costs	(95,399)		0
Accounts payable and accrued expenses	(356,548)		46,626
Deferred revenue	(139,680)		(907,776)
Net cash provided by operating activities	12,274,099		9,371,866
Cash flows from investing activities:
Maturity of marketable investments	58,380,000		43,579,082
Purchases of marketable investments	(64,618,676)		(50,933,705)
Net cash used in investing activities	(6,238,676)		(7,354,623)
Cash flows from financing activities:
Proceeds from stock option exercises	2,570,830		258,250
Payments for repurchase of common stock	(2,559,050)		(616,499)
Net cash provided by (used in) financing activities	11,780		(358,249)
Increase in cash and cash equivalents	6,047,203		1,658,994
Cash and cash equivalents at beginning of year	7,333,810		4,763,364
Cash and cash equivalents at end of period	13,381,013		6,422,358
Cash paid during the period for:
Interest	0		0
Taxes	$ 3,917,572		$ 4,410,000

[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. 3-Summary of Significant Accounting Policies for additional discussion.