Note 8 - Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Stock-based compensation	$ 9,545	$ 9,980
Goodwill and intangible assets	5,874	6,524
Allowance for doubtful accounts	3,537	3,822
Deferred rent	696	909
Tenant improvements	569	669
Estimated liability for appeals	5,632	7,775
Net operating loss carry-forwards	1,527	3,358
Tax credit carry-forwards	4,076	3,667
Property and equipment	49	256
Accrued expenses and other	7,839	3,615
Total deferred tax assets	39,344	40,575
Deferred tax liabilities:
Goodwill and intangible assets	43,400	48,186
Section 481(a) adjustment	5,073	7,413
Prepaid expenses	668	624
Capitalized software cost	8,688	6,341
Total deferred tax liabilities	57,829	62,564
Total net deferred tax liabilities	$ 18,485	$ 21,989