CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Treasury stock, shares	7,648,000	7,285,000
Class A
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	330,000,000	330,000,000
Common stock, shares issued	15,850,000	15,837,000
Common stock, shares outstanding	8,202,000	8,552,000
Class B Convertible
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	165,000,000	165,000,000
Common stock, shares issued	2,035,000	2,035,000
Common stock, shares outstanding	2,035,000	2,035,000