CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Preferred stock, par value (in Dollars per Share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in Shares)	5,000,000	5,000,000
Preferred stock, shares issued (in Shares)	0	0
Preferred stock, shares outstanding (in Shares)	0	0
Common stock, par value (in Dollars per Share)	$ 0.001	$ 0.001
Common stock, shares authorized (in Shares)	100,000,000	100,000,000
Common stock, shares issued (in Shares)	30,977,000	30,729,000
Treasury stock, shares (in Shares)	1,558,000	679,000