CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Consolidated Balance Sheets
Accounts receivable, allowance for doubtful accounts	$ 513,000	$ 461,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	34,669,276	34,350,329
Common stock, shares outstanding	34,669,276	34,350,329