Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2015

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, 2015	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	10,824	$	—	$	—	$	10,824
U.S. treasuries		5,035		—		—		5,035
Corporate bonds		—		2,005		—		2,005
Government-sponsored enterprise securities		—		2,000		—		2,000
Auction rate securities		—		—		2,077		2,077
	$	15,859	$	4,005	$	2,077	$	21,941

	Fair Value Measurements
December 31, 2014	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	8,674	$	—	$	—	$	8,674
Money market funds		169		—		—		169
U.S. treasuries		5,557		—		—		5,557
Corporate bonds		—		2,020		—		2,020
Government-sponsored enterprise securities		—		7,493		—		7,493
Auction rate securities		—		—		1,971		1,971
	$	14,400	$	9,513	$	1,971	$	25,884

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):

Balance at December 31, 2014	$	1,971
Total unrealized gains, excluding tax impact, included in other comprehensive loss		106
Balance at September 30, 2015	$	2,077
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	$	—