Financial Instruments

12 Months Ended

Dec. 31, 2019

Investments All Other Investments [Abstract]

5.	Financial Instruments

Cash equivalents, restricted cash and short-term investments, which are classified as available-for-sale securities, consisted of the following (in thousands):

December 31, 2019	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	15,369	$	—	$	—	$	15,369
U.S. government agency securities		51,467		23		—		51,490
Federal agency securities		9,995		11		—		10,006
Total financial assets	$	76,831	$	34	$	—	$	76,865
Classified as:
Cash and cash equivalents							$	15,369
Short-term investments								61,496
							$	76,865

December 31, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Money market funds (cash equivalents)	$	29,090	$	—	$	—		$	29,090
Federal agency securities (cash equivalents)		999		—	$	—			999
Restricted cash		50		—		—			50
U.S. government agency securities		74,144		1		(6	)		74,139
Federal agency securities		14,774		1		—			14,775
Total financial assets	$	119,057	$	2	$	(6	)	$	119,053
Classified as:
Cash and cash equivalents								$	30,089
Short-term investments									88,914
Restricted cash									50
								$	119,053

As of December 31, 2019, the remaining contractual maturities of available-for-sale debt securities was less than one year. There have been no material realized gains or losses on available-for-sale debt securities for the periods presented. The carrying amounts of cash, other assets, accounts receivable, accounts payable and other payables approximate their fair values due to the short-term maturity of these instruments.