Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Consolidated Statements of Comprehensive Income
Net income	$ 4,222	$ 27,858	$ 7,145	$ 15,516
Other comprehensive (loss) income:
Unrealized net gain (loss) on marketable securities	44	(36)	47	(35)
Other comprehensive income (loss):	44	(36)	47	(35)
Comprehensive income	$ 4,266	$ 27,822	$ 7,192	$ 15,481