Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities Measured at Fair Value

The following table presents our financial assets and liabilities that are carried at fair value, classified according to the three categories described above (in thousands):

	Fair Value Measurement at March 31, 2018
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents—money market funds	$	3,072	$	3,072	$	—	$	—
Cash equivalents—commercial paper		16,476		—		16,476		—
Cash equivalents—corporate bonds		1,507		—		1,507		—
Cash equivalents—U.S. government and agency securities		7,487		7,487		—		—
Restricted cash equivalents—money market fund		10,000		10,000		—		—
Total current assets		38,542		20,559		17,983		—
Restricted cash equivalents—money market fund		6,000		6,000		—		—
Total long term assets		6,000		6,000		—		—
Total assets	$	44,542	$	26,559	$	17,983	$	—
	Fair Value Measurement at December 31, 2017
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents—money market funds	$	2,014	$	2,014	$	—	$	—
Cash equivalents—commercial paper		16,477		—		16,477		—
Cash equivalents—corporate bonds		1,457		—		1,457		—
Cash equivalents—U.S. government and agency securities		10,488		10,488		—		—
Restricted cash equivalents—money market fund		3,000		3,000		—		—
Restricted cash equivalents—U.S. government and agency security fund		8,987		8,987		—		—
Total current assets		42,423		24,489		17,934		—
Restricted cash equivalents—money market fund		6,000		6,000		—		—
Total long term assets		6,000		6,000		—		—
Total assets	$	48,423	$	30,489	$	17,934	$	—