Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2016

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, 2016	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	10,940	$	—	$	—	$	10,940
Money market funds		6,590		—		—		6,590
U.S. treasuries		18,785		—		—		18,785
Auction rate securities		—		—		2,217		2,217
	$	36,315	$	—	$	2,217	$	38,532

	Fair Value Measurements
December 31, 2015	Level 1		Level 2		Level 3		Total
Certificates of deposit	$	15,239	$	—	$	—	$	15,239
U.S. treasuries		7,019		—		—		7,019
Corporate bonds		—		1,000		—		1,000
Auction rate securities		—		—		2,052		2,052
	$	22,258	$	1,000	$	2,052	$	25,310

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, 2015	$	2,052
Total unrealized gains, excluding tax impact, included in other comprehensive loss		165
Balance at September 30, 2016	$	2,217
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	$	—