Note 2 - Summary of Significant Accounting Policies - Weighted Average Common Shares (Details) - shares	3 Months Ended														12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[2]	Jun. 30, 2018	[3],[4]	Mar. 31, 2018	[5]	Dec. 31, 2017	[6],[7]	Sep. 30, 2017	[8]	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Weighted average common shares outstanding–basic (in shares)	10,367,132		10,355,673		10,342,674		10,326,309		10,308,243		10,288,325		10,277,155	10,264,565	10,347,947	10,284,572
Potentially dilutive securities:
Unvested shares of restricted stock and employee stock options (in shares)															34,247	54,741
Weighted average common shares and common share equivalents outstanding – diluted (in shares)	10,367,132		10,355,673		10,370,318		10,365,306		10,308,243		10,351,009		10,334,894	10,295,337	10,382,194	10,339,313
Average number of potentially dilutive securities excluded from calculation (in shares)															216,420	77,047

[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 Notes 2 and 12.

[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.

[6] The quarter ended December 31, 2017 includes a $7,525 increase in the fair value of contingent consideration, which was not deductible for tax purposes.

[7] The quarter ended December 31, 2017 includes adjustments related to tax legislation enacted in December 2017, as discussed in Note 2 and 12.

[8] The quarter ended September 30, 2017 includes a $549 reduction in the fair value of contingent consideration, which was not taxable.