Unaudited Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Allowance	$ 106	$ 59
Common Class A [Member]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	140,000,000	140,000,000
Common stock, shares issued (in shares)	33,187,065	32,859,292
Common stock, shares outstanding (in shares)	33,187,065	32,859,292
Common Class B [Member]
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	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