Cash, Cash Equivalents, and Short-Term Investments (Tables)

9 Months Ended

Sep. 30, 2017

Cash And Cash Equivalents [Abstract]

Summary of Cash, Cash Equivalents and Short-Term Investments

Cash, cash equivalents and short-term investments consist of the following (in thousands):

	As of September 30, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Cash and cash equivalents:
Cash	$	76,134	$	-	$	-	$	76,134
Commercial paper		2,999		-				2,999
Money market funds		84,802		-		-		84,802
Total	$	163,935	$	-	$	-	$	163,935
Short-term investments:
Commercial paper	$	16,649	$	-	$	5	$	16,644
Corporate debt obligations		147,383		1		207		147,177
US government agencies		14,998		-		30		14,968
Bank deposits		480		-				480
Total	$	179,510	$	1	$	242	$	179,269

	As of December 31, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Cash and cash equivalents:
Cash	$	63,642	$	-	$	-	$	63,642
Commercial paper		6,995		-		2		6,993
Money market funds		36,708		-		-		36,708
Total	$	107,345	$	-	$	2	$	107,343
Short-term investments:
Commercial paper	$	14,245	$	-	$	8	$	14,237
Corporate debt obligations		110,062		-		347		109,715
US government agencies		18,998		2		50		18,950
Bank deposits		10,846		1		-		10,847
Total	$	154,151	$	3	$	405	$	153,749

Summary of Cost and Estimated Fair Value of Short-Term Investments

The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of September 30, 2017 (in thousands):

	As of September 30, 2017
			Estimated
	Amortized		Fair
	Cost		Value
Short-term investments:
Due within one year	$	111,172	$	111,045
Due within two years		68,338		68,224
Total	$	179,510	$	179,269

Schedule of Short-Term Investments at Fair Value and Length of Continuous Unrealized Loss Position

The following tables show the short-term investments in an unrealized loss position and the related gross unrealized losses and fair value and length of time that the short-term investments have been in a continuous unrealized loss position (in thousands):

	As of September 30, 2017
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	14,919	$	5	$	-	$	-	$	14,919	$	5
Corporate debt obligations		92,500		151		50,152		56		142,652	$	207
US government agencies		-		-		14,968		30		14,968		30
Bank deposits		480		-		-		-		480	$	-
	$	107,899	$	156	$	65,120	$	86	$	173,019	$	242

	As of December 31, 2016
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	14,237	$	8	$	-	$	-	$	14,237	$	8
Corporate debt obligations		78,821		323		29,689		24		108,510	$	347
US government agencies		11,451		46		3,496		4		14,947		50
	$	104,509	$	377	$	33,185	$	28	$	137,694	$	405