Investments

The following table summarizes the investments in marketable securities by investment category:

	March 31, 201 9				December 31, 201 8
	Cost		Fair Value		Cost		Fair Value
Available-for-sale securities:
Municipal bonds	$	6,913	$	6,908	$	6,751	$	6,733
Corporate notes/bonds		146,185		146,321		146,466		146,126
Variable rate demand notes		8,900		8,900		8,900		8,900
Asset backed securities		30,623		30,627		32,986		32,923
Commercial paper		17,433		17,432		39,707		39,701
Certificate of deposit		818		818		956		956
Total investments	$	210,872	$	211,006	$	235,766	$	235,339

As of

March 31, 2019,

the Company had

investments that were in an unrealized loss position. The gross unrealized losses on these investments at

March 31, 2019

$102

were determined to be temporary in nature. The Company reviews the investments to identify and evaluate investments that have an indication of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value.

The contractual maturities of available-for-sale securities at

March 31, 2019

are presented in the following table:

	Cost		Fair Value
Due in one year or less	$	111,278	$	111,267
Due between one and five years		87,292		87,445
Due after five years		12,302		12,294
	$	210,872	$	211,006

The Company has a marketable equity investment in a company located in Taiwan. The fair value of the investment and unrealized loss as of

March 31, 2019

was

$1,659

and

$335,

respectively. This investment is included in Other assets, net on the condensed consolidated balance sheets.

The Company has non-marketable equity investments in privately held companies without readily determinable market values. 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 (expense), net. As of

March 31, 2019,

non-marketable equity investments had a carrying value of approximately

$16,866,

of which

$6,066

was remeasured to fair value based on observable transaction during the

three

months ended

March 31, 2018.

These investments are included in Other assets, net on the condensed consolidated balance sheets. The unrealized gain recorded in other income and included as adjustment to the carrying value of non-marketable equity investments held was

$3,066

for the

three

months ended

March 31, 2018.