CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Investments, measured at fair value	$ 1,902	$ 25,071
Liabilities and shareholders’ equity
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	23,153,000	23,125,000
Common stock, shares outstanding	23,152,000	23,070,000
Treasury stock, common shares held	1,000	55,000