Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance	$ 63	$ 59
Class A common stock
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	140,000,000	140,000,000
Common stock, shares issued (in shares)	33,314,141	32,859,292
Common stock, shares outstanding (in shares)	33,314,141	32,859,292
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares issued (in shares)	15,687,101	15,486,560
Common stock, shares outstanding (in shares)	15,687,101	15,486,560