Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurement

The following tables represent the financial instruments measured at fair value on a recurring basis on the financial statements of the Company and the valuation approach applied to each class of financial instruments at March 31, 2018 and December 31, 2017 (in thousands):

	March 31, 2018
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Cash and cash equivalents
Money market funds	$	21,918	$	—	$	—	$	21,918
Investments:
Certificates of deposit	—		13,936		—		13,936
U.S. Treasury securities	18,863		—		—		18,863
U.S. Agency securities	—		6,941		—		6,941
Commercial paper	—		2,791		—		2,791
Corporate notes and bonds	—		24,223		—		24,223
Total investments	18,863		47,891		—		66,754
Total assets measured at fair value	$	40,781	$	47,891	$	—	$	88,672

	December 31, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Cash and cash equivalents:
Money market funds	$	7,832	$	—	$	—	$	7,832
Investments:
Certificates of deposit	—		13,441		—		13,441
U.S. Treasury securities	14,716		—		—		14,716
U.S. Agency securities	—		8,459		—		8,459
Commercial paper	—		9,171		—		9,171
Asset-backed securities	—		3,025		—		3,025
Corporate notes and bonds	—		31,836		—		31,836
Total investments	14,716		65,932		—		80,648
Total assets measured at fair value	$	22,548	$	65,932	$	—	$	88,480