Note 2. Investments and Fair Value Measurements

Our cash and cash equivalents consist of cash and instruments with original maturities of less than three months. Our investments consist of instruments with original maturities of more than three months. As of March 31, 2018 and December 31, 2017, our cash, cash equivalents and investments are classified as follows (in thousands):


	March 31, 2018								December 31, 2017
			Gross		Gross						Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
	Cost		Gain		(Loss)		Value		Cost		Gain		(Loss)		Value
Classified as:
Cash	$	39,189	$	—	$	—	$	39,189	$	43,610	$	—	$	—	$	43,610
Cash equivalents:
Certificates of deposit 1		—		—		—		—		742		—		—		742
Total cash and cash equivalents		39,189		—		—		39,189		44,352		—		—		44,352
Investments (available-for-sale):
Certificates of deposit 2		7,340		—		(41)		7,299		7,099		—		(24)		7,075
Corporate bonds		20,576		—		(169)		20,407		25,602		—		(69)		25,533
Total investments		27,916		—		(210)		27,706		32,701		—		(93)		32,608
Total cash, cash equivalents and investments	$	67,105	$	—	$	(210)	$	66,895	$	77,053	$	—	$	(93)	$	76,960
Contractual maturities on investments:
Due within 1 year 3	$	15,288					$	15,195	$	20,056					$	20,032
Due after 1 through 5 years 4		12,628						12,511		12,645						12,576
	$	27,916					$	27,706	$	32,701					$	32,608

Certificates of deposit with original maturities of less than three months.

Certificates of deposit with original maturities of more than three months.

Classified as “Short-term investments” in our condensed consolidated balance sheets.

Classified as “Long-term investments” in our condensed consolidated balance sheets.

We manage our investments as a single portfolio of highly marketable securities that is intended to be available to meet our current cash requirements. Certificates of deposit and corporate bonds are typically held until maturity. Corporate equity securities have no maturity and may be sold at any time.

Our holding of corporate equity securities consists of common stock of GCS Holdings, Inc. (“GHI”) (previously Global Communication Semiconductors, Inc.), a Taiwan publicly-traded company. We began classifying GHI as an available-for-sale security in the second quarter of 2015 when we determined that there was sufficient trading volume in the exchange for the stock to be deemed readily marketable. During the three months ended March 31, 2017, we sold the remainder of our GHI stock and our cash proceeds from sales of available-for-sale investments were $125,000. Our cost was $48,000 and our gross realized gain from sales of available-for-sale investments was $77,000. There were no GHI transactions in the three months ended March 31, 2018. As of March 31, 2017, we no longer hold any GHI stock.

The gross unrealized losses related to our portfolio of available-for-sale securities were primarily due to changes in interest rates and market and credit conditions of the underlying securities. We have determined that the gross unrealized losses on our available-for-sale securities as of March 31, 2018 are temporary in nature. We periodically review our investment portfolio to identify and evaluate investments that have indications of possible impairment. Factors considered in determining whether a loss is temporary include the magnitude of the decline in market value, the length of time the market value has been below cost (or adjusted cost), credit quality, and our ability and intent to hold the securities for a period of time sufficient to allow for any anticipated recovery in market value.

A portion of our investments would generate a loss if we sold them on March 31, 2018. The following table summarizes the fair value and gross unrealized losses related to available-for-sale securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2018 (in thousands):


	In Loss Position				In Loss Position				Total In
	< 12 months				> 12 months				Loss Position
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
As of March 31, 2018	Value		(Losses)		Value		(Losses)		Value		(Losses)
Investments:
Certificates of deposit	$	4,935	$	(35)	$	2,344	$	(6)	$	7,279	$	(41)
Corporate bonds		13,153		(107)		7,254		(62)		20,407		(169)
Total in loss position	$	18,088	$	(142)	$	9,598	$	(68)	$	27,686	$	(210)

The following table summarizes the fair value and gross unrealized losses related to available-for-sale securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of December 31, 2017 (in thousands):


	In Loss Position				In Loss Position				Total In
	< 12 months				> 12 months				Loss Position
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
As of December 31, 2017	Value		(Loss)		Value		(Loss)		Value		(Loss)
Investments:
Certificates of deposit	$	3,994	$	(16)	$	2,342	$	(8)	$	6,336	$	(24)
Corporate bonds		25,533		(69)		—		—		25,533		(69)
Total in loss position	$	29,527	$	(85)	$	2,342	$	(8)	$	31,869	$	(93)

Investments in Privately-held Companies

We have made strategic investments in private companies located in China in order to gain access at a competitive cost to raw materials that are critical to our substrate business (see Note 7). The investment balances for all of these companies, including minority investments indirectly in privately-held companies made by our consolidated subsidiaries, are accounted for under the equity method and included in “Other assets” in the condensed consolidated balance sheets and totaled $9.7 million and $9.8 million as of March 31, 2018 and December 31, 2017, respectively. As of March 31, 2018, there were seven companies accounted for under the equity method. There were no impairment charges in the three months ended March 31, 2018. The three months ended March 31, 2017 include an impairment charge of $313,000 for one of the gallium companies. During the first quarter of 2017, management determined that it was unlikely that this company would recover from the difficult pricing environment and we had written the investment down to zero.

Fair Value Measurements

We invest primarily in money market accounts, certificates of deposits, corporate bonds and notes, and government securities. Accounting Standards Codification (“ASC”) Topic 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes three levels of inputs that may be used to measure fair value. Level 1 instrument valuations are obtained from real-time quotes for transactions in active exchange markets of the asset or identical assets. Level 2 instrument valuations are obtained from readily-available, observable pricing sources for comparable instruments. Level 3 instrument valuations are obtained from unobservable inputs in which there is little or no market data, which require us to develop our own assumptions. On a recurring basis, we measure certain financial assets and liabilities at fair value, primarily consisting of our short-term and long-term investments.

The type of instrument valued based on quoted market prices in active markets include our money market funds, which are generally classified within Level 1 of the fair value hierarchy. Other than corporate equity securities which are based on quoted market prices and classified as Level 1, we classify our available-for-sale securities including certificates of deposit and corporate bonds as having Level 2 inputs. The valuation techniques used to measure the fair value of these financial instruments having Level 2 inputs were derived from bank statements, quoted market prices, broker or dealer statements or quotations, or alternative pricing sources with reasonable levels of price transparency.

We place short-term foreign currency hedges that are intended to offset the potential cash exposure related to fluctuations in the exchange rate between the United States dollar and Japanese Yen. We measure the fair value of these foreign currency hedges at each month end and quarter end using current exchange rates and in accordance with generally accepted accounting principles. At quarter end any foreign currency hedges not settled are netted in “Accrued liabilities” on the condensed consolidated balance sheet and classified as Level 3 assets and liabilities. As of March 31, 2018, the net change in fair value from the placement of the hedge to settlement at each month end during the quarter had a de minimis impact to the consolidated results.

There were no changes in valuation techniques or related inputs in the three months ended March 31, 2018. There have been no transfers between fair value measurements levels during the three months ended March 31, 2018.

The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis in accordance with ASC 820 as of March 31, 2018 (in thousands):


			Quoted Prices in				Significant
			Active Markets of		Significant Other		Unobservable
	Balance as of		Identical Assets		Observable Inputs		Inputs
	March 31, 2018		(Level 1)		(Level 2)		(Level 3)
Assets:
Cash equivalents and investments:
Certificates of deposit	$	7,299	$	—	$	7,299	$	—
Corporate bonds		20,407		—		20,407		—
Total	$	27,706	$	—	$	27,706	$	—

The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis in accordance with ASC 820 as of December 31, 2017 (in thousands):


			Quoted Prices in				Significant
			Active Markets of		Significant Other		Unobservable
	Balance as of		Identical Assets		Observable Inputs		Inputs
	December 31, 2017		(Level 1)		(Level 2)		(Level 3)
Assets:
Cash equivalents and investments:
Certificates of deposit	$	7,817	$	—	$	7,817	$	—
Corporate bonds		25,533		—		25,533		—
Total	$	33,350	$	—	$	33,350	$	—

Items Measured at Fair Value on a Nonrecurring Basis

Certain assets that are subject to nonrecurring fair value measurements are not included in the table above. These assets include investments in privately-held companies accounted for by the equity or cost method (See Note 7). There were no impairment charges in the three months ended March 31, 2018. The three months ended March 31, 2017 include an impairment charge of $313,000 for one of the gallium companies. During the first quarter of 2017, management determined that it was unlikely that this company would recover from the difficult pricing environment and we had written the investment down to zero. Except as mentioned, we did not record other-than-temporary impairment charges for the remainder of these investments during the three months ended March 31, 2018 and 2017.