Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on Recurring Basis

Assets and liabilities measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014 are summarized below (in thousands):

	March 31, 2015
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	8,451	$	—	$	8,451
Corporate debt securities		—		—		—
Total cash equivalents		8,451		—		8,451
Short-term investments:
Corporate commercial paper		—		1,199		1,199
Corporate debt securities		—		15,447		15,447
Total short-term investments		—		16,646		16,646
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	8,701	$	16,646	$	25,347

	December 31, 2014
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	9,362	$	—	$	9,362
Corporate debt securities		—		1,002		1,002
Total cash equivalents		9,362		1,002		10,364
Short-term investments:
Corporate commercial paper		—		550		550
Corporate debt securities		—		12,713		12,713
Total short-term investments		—		13,263		13,263
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	9,612	$	14,265	$	23,877