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

12 Months Ended

Dec. 31, 2019

Notes to Financial Statements

Cash, Cash Equivalents, Investments, and Restricted Cash Disclosure [Text Block]

3.  CASH, CASH EQUIVALENTS, INVESTMENTS AND RESTRICTED CASH

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

	December 31,
	2019		2018
Cash, cash equivalents and investments:
Cash	$	144,860	$	131,569
Money market funds		28,100		41,135
Corporate debt securities		260,950		170,909
Commercial paper		1,994		-
U.S. treasuries and government agency bonds		19,493		32,068
Certificates of deposit		-		1,600
Auction-rate securities backed by student-loan notes		3,138		3,241
Total	$	458,535	$	380,522

	December 31,
	2019		2018
Reported as:
Cash and cash equivalents	$	172,960	$	172,704
Short-term investments		282,437		204,577
Long-term investments		3,138		3,241
Total	$	458,535	$	380,522

The contractual maturities of the Company’s short-term and long-term available-for-sale investments are as follows (in thousands):

	December 31,
	2019		2018
Due in less than 1 year	$	147,532	$	125,845
Due in 1 - 5 years		134,905		78,732
Due in greater than 5 years		3,138		3,241
Total	$	285,575	$	207,818

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

	December 31, 2019
	Amortized Cost		Unrealized Gains		Unrealized Losses			Total Fair Value		Fair Value of Investments in Unrealized Loss Position
Money market funds	$	28,100	$	-	$	-		$	28,100	$	-
Corporate debt securities		260,645		383		(78	)		260,950		93,262
Commercial paper		1,994		-		-			1,994		-
U.S. treasuries and government agency bonds		19,487		7		(1	)		19,493		993
Auction-rate securities backed by student-loan notes		3,320		-		(182	)		3,138		3,138
Total	$	313,546	$	390	$	(261	)	$	313,675	$	97,393

	December 31, 2018
	Amortized Cost		Unrealized Gains		Unrealized Losses			Total Fair Value		Fair Value of Investments in Unrealized Loss Position
Money market funds	$	41,135	$	-	$	-		$	41,135	$	-
Corporate debt securities		172,288		7		(1,386	)		170,909		166,204
U.S. treasuries and government agency bonds		32,207		2		(141	)		32,068		28,507
Certificates of deposit		1,600		-		-			1,600		-
Auction-rate securities backed by student-loan notes		3,570		-		(329	)		3,241		3,241
Total	$	250,800	$	9	$	(1,856	)	$	248,953	$	197,952

As of  December 31, 2019 and 2018, unrealized losses that had been in a continuous loss position for 12 months or longer were $0.2 million and $1.6 million, respectively. 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 other-than-temporary impairment, management reviewed 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. As of  December 31, 2019 and 2018, the Company did not consider any of its available-for-sale investments to be other-than-temporarily impaired.

The Company redeemed $0.3 million and $2.0 million of its auction-rate securities at face value for the years ended December 31, 2019 and 2018, respectively. There were no sales of auction-rate securities for the year ended December 31, 2017. The underlying maturities of the remaining auction-rate securities are up to 27 years. As of December 31, 2019 and 2018, the impairment of $0.2 million and $0.3 million, respectively, was determined to be temporary because management possessed both the intent and ability to hold these securities for a period of time sufficient to allow for any anticipated recovery in fair value. In addition, management believed that it was more likely than not that the Company would not have to sell these securities before recovery of its amortized cost basis. All scheduled interest payments have been received on time pursuant to the terms and conditions of the securities. To date, the Company has redeemed $40.0 million, or 92% of the original portfolio in these auction-rate securities, at par without any realized losses.

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,
	2019		2018
Cash and cash equivalents	$	172,960	$	172,704
Restricted cash included in other long-term assets		116		114
Total cash, cash equivalents and restricted cash reported on the Consolidated Statements of Cash Flows	$	173,076	$	172,818

As of  December 31, 2019 and 2018, 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.