Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Summary of Cash Equivalents, Marketable Securities and Long-Term Investments Measured at Fair Value

Cash equivalents, marketable securities and long-term investments measured at fair value are classified in the table below in one of the three categories described above (in thousands):

	Fair Value Measurements
September 30, 2013	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	1,171	$	—	$	—	$	1,171
Money market funds		12,774		—		—		12,774
U.S. treasuries		4,012		—		—		4,012
Corporate bonds		—		4,853		—		4,853
Government-sponsored enterprise securities		—		7,000		—		7,000
Auction rate securities		—		—		2,039		2,039
	$	17,957	$	11,853	$	2,039	$	31,849

	Fair Value Measurements
December 31, 2012	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	496	$	—	$	—	$	496
Money market funds		18,500		—		—		18,500
U.S. treasuries		10,136		—		—		10,136
Corporate bonds		—		11,501		—		11,501
Government-sponsored enterprise securities		—		15,506		—		15,506
Auction rate securities		—		—		2,225		2,225
	$	29,132	$	27,007	$	2,225	$	58,364

Summary of Activity for Assets Measured at Fair Value Using Significant Unobservable Inputs

Activity for assets measured at fair value using significant unobservable inputs (Level 3) is presented in the table below (in thousands):

	Nine Months Ended September 30, 2013
Balance at December 31, 2012	$	2,225
Total net unrealized losses, excluding tax impact, included in other comprehensive income		(186	)
Balance at September 30, 2013	$	2,039
Total gains or losses for the period included in net loss attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	$	—