Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Summary of Assets Measured at Fair Value on Recurring Basis

The following tables present the balances of assets measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the date presented (in thousands):

	March 31, 2017
	LEVEL 1		LEVEL 2
	(in thousands)
Cash equivalents:
Money market funds	$	1,364	$	—
U.S. government agency securities		—		2,496
Commercial paper		—		999
Short-term investments:
U.S. government agency securities		—		48,885
Corporate notes and bonds		—		19,725
Commercial paper		—		7,625
Total assets measured at fair value	$	1,364	$	79,730

	December 31, 2016
	LEVEL 1		LEVEL 2
	(in thousands)
Cash equivalents:
Money market funds	$	14,065	$	—
U.S. government agency securities		—		4,997
Corporate notes and bonds		—		959
Commercial paper		—		2,948
Short-term investments:
U.S. government agency securities		—		36,531
Corporate notes and bonds		—		19,252
Commercial paper		—		11,122
Total assets measured at fair value	$	14,065	$	75,809