Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	[1]	Sep. 30, 2018	[2]	Jun. 30, 2018	[3],[4]	Mar. 31, 2018	[5]	Dec. 31, 2019	Dec. 31, 2018
Weighted average common shares outstanding–basic (in shares)	10,274,980	10,421,383	10,411,276	10,385,017	10,367,132		10,355,673		10,342,674		10,326,309		10,373,164	10,347,947
Unvested shares of restricted stock and employee stock options (in shares)													18,811	34,247
Weighted average common shares and common share equivalents outstanding – diluted (in shares)	10,298,535	10,429,536	10,411,276	10,414,330	10,367,132		10,355,673		10,370,318		10,365,306		10,391,975	10,382,194
Average number of potentially dilutive securities excluded from calculation (in shares)													523,485	216,420

[1] The quarter ended December 31, 2018 includes a $2,828 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[2] The quarter ended September 30, 2018 includes $3,057 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[3] The quarter ended June 30, 2018 includes a $710 reduction in the fair value of contingent consideration, which was not taxable.

[4] The quarter ended June 30, 2018 includes the reversal of certain adjustments originally recorded in the quarter ended December 31, 2017 which were related to tax legislation enacted in December 2017, as discussed in Note 10.

[5] The quarter ended March 31, 2018 includes a $1,726 increase in the fair value of contingent consideration, which was not deductible for tax purposes.