Note 3 - Cash, Cash Equivalents, Investments and Restricted Cash

12 Months Ended

Dec. 31, 2021

Notes to Financial Statements

Financial Instruments Disclosure [Text Block]

3.  CASH, CASH EQUIVALENTS, INVESTMENTS AND RESTRICTED CASH

The following is a summary of the Company’s cash, cash equivalents and debt investments (in thousands): 

	December 31,
	2021		2020
Cash	$	174,937	$	300,609
Money market funds		14,328		34,335
Certificates of deposit		141,478		-
Corporate debt securities		386,883		249,671
Commercial paper		-		2,999
U.S. treasuries and government agency bonds		7,456		7,499
Auction-rate securities backed by student-loan notes		2,401		2,861
Total	$	727,483	$	597,974

	December 31,
	2021		2020
Reported as:
Cash and cash equivalents	$	189,265	$	334,944
Short-term investments		535,817		260,169
Investment within other long-term assets		2,401		2,861
Total	$	727,483	$	597,974

The following table summarizes the contractual maturities of the short-term and long-term available-for-sale investments as of December 31, 2021 (in thousands): 

	Amortized Cost		Fair Value
Due in less than 1 year	$	123,204	$	123,381
Due in 1 - 5 years		413,850		412,436
Due in greater than 5 years		2,520		2,401
Total	$	539,574	$	538,218

For the year ended December 31, 2020, the Company recognized gross realized gains of $1.1 million on the sale of investments. Gross realized gains and losses were not material for the other periods presented.

The following tables summarize the unrealized gain and loss positions related to the available-for sale investments (in thousands): 

	December 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	14,328	$	-	$	-		$	14,328
Certificates of deposit		141,478		-		-			141,478
Corporate debt securities		388,081		570		(1,768	)		386,883
U.S. treasuries and government agency bonds		7,495		-		(39	)		7,456
Auction-rate securities backed by student-loan notes		2,520		-		(119	)		2,401
Total	$	553,902	$	570	$	(1,926	)	$	552,546

	December 31, 2020
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Money market funds	$	34,335	$	-	$	-		$	34,335
Corporate debt securities		247,591		2,177		(97	)		249,671
Commercial paper		2,999		-		-			2,999
U.S. treasuries and government agency bonds		7,499		2		(2	)		7,499
Auction-rate securities backed by student-loan notes		3,020		-		(159	)		2,861
Total	$	295,444	$	2,179	$	(258	)	$	297,365

The following tables present information about the available-for-sale investments that had been in a continuous unrealized loss position for less than 12 months and for greater than 12 months (in thousands):

	December 31, 2021
	Less than 12 Months					Greater than 12 Months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate debt securities	$	285,954	$	(1,765	)	$	4,760	$	(3	)	$	290,714	$	(1,768	)
U.S. treasuries and government agency bonds		7,456		(39	)		-		-			7,456		(39	)
Auction-rate securities backed by student-loan notes		-		-			2,401		(119	)		2,401		(119	)
Total	$	293,410	$	(1,804	)	$	7,161	$	(122	)	$	300,571	$	(1,926	)

	December 31, 2020
	Less than 12 Months					Greater than 12 Months					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate debt securities	$	59,144	$	(97	)	$	-	$	-		$	59,144	$	(97	)
U.S. treasuries and government agency bonds		5,998		(2	)		-		-			5,998		(2	)
Auction-rate securities backed by student-loan notes		-		-			2,861		(159	)		2,861		(159	)
Total	$	65,142	$	(99	)	$	2,861	$	(159	)	$	68,003	$	(258	)

An impairment exists when the fair value of an investment is less than its amortized cost basis. As of December 31, 2021 and 2020, the Company did not consider the impairment of its investments to be a result of credit losses. The Company typically invests in highly rated securities, with the primary objective of minimizing the potential risk of principal loss. The Company’s investment policy generally requires securities to be investment grade and limits the amount of credit exposure to any one issuer. When evaluating a debt security for impairment, management reviews factors such as the Company’s intent to sell, or whether it will more likely than not be required to sell, the security before recovery of its amortized cost basis, the extent to which the fair value of the security is less than its cost, the financial condition of the issuer and the credit quality of the investment.

The Company’s auction-rate securities are backed by pools of student loans supported by guarantees by the U.S. Department of Education. The underlying maturities of these securities are up to 24 years. The Company has received all scheduled interest payments on a timely basis pursuant to the terms and conditions of the securities. The Company does not intend to sell these securities, and it is more likely than not that the Company will not be required to sell these securities, before recovery of its amortized cost basis. To date, the Company has redeemed $40.8 million, or 94% of the original portfolio in these auction-rate securities, at par without any realized losses.

Non-Marketable Equity Investment

In November 2020, the Company made an equity investment in a privately held Swiss company (the “Investee”) that is accounted for under the measurement alternative. One member of the Company’s Board of Directors is an executive officer of a company that has a commercial relationship with the Investee. In addition, the Company’s Chief Executive Officer has a personal investment in the Investee. As of December 31, 2021 and 2020, the Company’s investment in the Investee, which is denominated in CHF, had a carrying value of $3.3 million and $3.4 million, respectively. The Company did not record any impairment or adjustments resulting from observable price changes for the years ended December 31, 2021 and 2020.

Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported on the Consolidated Balance Sheets to the amounts reported on the Consolidated Statements of Cash Flows (in thousands):   

	December 31,
	2021		2020
Cash and cash equivalents	$	189,265	$	334,944
Restricted cash included in other long-term assets		124		127
Total cash, cash equivalents and restricted cash reported on the Consolidated Statements of Cash Flows	$	189,389	$	335,071

As of  December 31, 2021 and 2020, restricted cash included a security deposit that is set aside in a bank account and cannot be withdrawn by the Company under the terms of a lease agreement. The restriction will end upon the expiration of the lease.