Condensed Consolidated Balance Sheets (Parentheticals) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Allowance for doubtful accounts	$ 10,000,000.0	$ 6,969,000
Unamortized debt discount, current	0	0
Deferred Costs, Current	575,000	575,000
Unamortized debt discount, noncurrent	0	0
Deferred Costs, Noncurrent	$ 1,523,000	$ 1,811,000
Stockholders' Equity Note [Abstract]
Common stock, shares issued	30,529,840	30,567,725
Common stock, shares outstanding	30,529,840	30,567,725
Treasury stock, shares	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (per share)	$ 0.10	$ 0.10
Common stock, shares authorized	120,000,000	120,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares authorized	500,000	500,000
Preferred stock, par value (per share)	$ 0.10	$ 0.10