Unaudited Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Allowance	$ 69	$ 122
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	9,333,333	9,333,333
Preferred stock, shares issued (in shares)	0	0
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	140,000,000	30,000,000
Common stock, shares issued (in shares)	32,807,957	6,384,887
Common stock, shares outstanding (in shares)	32,807,957	6,384,887
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	35,000,000	0
Common stock, shares issued (in shares)	15,486,560	0
Common stock, shares outstanding (in shares)	15,486,560	0