Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

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 were as follows (in thousands):

	December 31, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	2,274	$	-	$	2,274
Corporate commercial paper		-		3,245		3,245
Corporate debt		-		1,000		1,000
Total cash equivalents		2,274		4,245		6,519
Short-term investments:
Corporate commercial paper		-		5,480		5,480
Corporate debt		-		6,415		6,415
Total short-term investments		-		11,895		11,895
Total assets measured at fair value	$	2,274	$	16,140	$	18,414
	December 31, 2016
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	2,796	$	-	$	2,796
Corporate commercial paper		-		500		500
Corporate debt		-		-		-
Total cash equivalents		2,796		500		3,296
Short-term investments:
Corporate commercial paper		-		11,465		11,465
Corporate debt		-		7,423		7,423
Total short-term investments		-		18,888		18,888
Total assets measured at fair value	$	2,796	$	19,388	$	22,184