CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 2,365	$ 13,759
Other comprehensive income:
Realized losses on short-term investments reclassified from accumulated other comprehensive income, net of tax of $1	3
Net change in unrealized gains and (losses) on available-for-sale investments, net of tax of $560	2,385
Comprehensive income	$ 4,753	$ 13,759