Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Allowance	$ 207	$ 63
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)	33,697,907	33,314,141
Common stock, shares outstanding (in shares)	33,697,907	33,314,141
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)	15,807,095	15,687,101
Common stock, shares outstanding (in shares)	15,807,095	15,687,101