Note 2 - Investments

12 Months Ended

Dec. 31, 2019

Notes to Financial Statements

Investment [Text Block]

2. Investments

The following table summarizes the investments by investment category:

	December 31, 2019
	Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Available-for-sale securities:
U.S. Treasury securities	$	3,752	$	7	$	—		$	3,759
Municipal bonds		6,062		57		—			6,119
Corporate notes/bonds		118,859		591		(1	)		119,449
Asset-backed securities		4,239		29		—			4,268
Commercial paper		6,464		1		(1	)		6,464
Certificate of deposit		72		—		—			72
Total investments	$	139,448	$	685	$	(2	)	$	140,131

	December 31, 2018
	Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Available-for-sale securities:
Municipal bonds	$	6,751	$	1	$	(19	)	$	6,733
Corporate notes/bonds		146,466		14		(354	)		146,126
Variable rate demand notes		8,900		—		—			8,900
Asset-backed securities		32,986		—		(63	)		32,923
Commercial paper		39,707		—		(6	)		39,701
Certificate of deposit		956		—		—			956
Total investments	$	235,766	$	15	$	(442	)	$	235,339

As of December 31, 2019, the Company had three investments that were in an unrealized loss position. The gross unrealized losses on these investments at December 31, 2019 were primarily due to changes in interest rates and determined to be temporary in nature. 

The realized gain related to the Company’s available-for-sale investment, which was reclassified from accumulated other comprehensive income, was included in other income, net in the consolidated statements of income (loss).

Contractual maturities of available-for-sale securities at December 31, 2019 are presented in the following table:

	Cost		Fair Value
Due in one year or less	$	88,803	$	89,049
Due between one and five years		50,645		51,082
	$	139,448	$	140,131

The Company has a marketable equity investment in a company located in Taiwan. The fair value of the investment and unrealized loss as of December 31, 2019 was $1,662 and $332, respectively. The fair value of the investment and unrealized loss as of December 31, 2018 was $1,387 and $607, respectively. This investment is presented within other assets, net on the consolidated balance sheet.  During the year ended December 31, 2019, the Company sold a marketable equity investment in a company located in the United States acquired in the same year for $3,424.  The gain on sale of $924 was included in other income, net in the consolidated statements of income (loss).

          The Company has non-marketable equity investments in privately held companies without readily determinable market values. Prior to January 1, 2018, the Company accounted for non-marketable equity investments at cost less impairment. Realized gains and losses on non-marketable equity investments sold or impaired were recognized in other income, net. On January 1, 2018, the Company adopted ASU 2016-01, Financial Instruments – Recognition and Measurement of Financial Assets and Financial Liabilities, which changed the way the Company accounts for non-marketable equity investments. The Company adjusts the carrying value of non-marketable equity investments to fair value upon observable transactions for identical or similar investments of the same issuer or impairment (referred to as the measurement alternative). All gains and losses on non-marketable equity investments, realized and unrealized, are recognized in other income, net. There was no cumulative effect adjustment upon adoption of this guidance. As of December 31, 2019, non-marketable equity investments had a carrying value of $25,792, of which $8,792 was remeasured to fair value based on observable transaction during the year ended December 31, 2019. As of December 31, 2018, non-marketable equity investments had a carrying value of $16,866, of which $6,066 was remeasured to fair value based on observable transaction during the year ended December 31, 2018.  These investments are presented within other assets, net on the consolidated balance sheets. The unrealized gain recorded in other income, net and included as adjustment to the carrying value of non-marketable equity investments held was $1,926 and $3,066 for the years ended December 31, 2019 and 2018, respectively. During the year ended December 31, 2018, the Company recorded an impairment charge of $7,000 related to a certain investment in a private company because the investee was in receivership and the Company was not expected to recover its cost.  The impairment charge was included in other income, net in the consolidated statements of income (loss).