Investments consist of the following as of December 31, 2019 and 2018 (dollars in thousands):

	December 31, 2019
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available for sale):
Municipal bonds	$	1,361	$	3	$	-		$	1,364
Non-governmental debt securities		165,423		433		(37	)		165,819
Treasury and federal agencies		18,307		7		(9	)		18,305
Total short-term investments (available for sale)	$	185,091	$	443	$	(46	)	$	185,488

	December 31, 2018
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available for sale):
Non-governmental debt securities	$	179,393	$	35	$	(337	)	$	179,091
Treasury and federal agencies		17,417		5		(85	)		17,337
Total short-term investments (available for sale)	$	196,810	$	40	$	(422	)	$	196,428

In the table above, unrealized holding gains (losses) relate to short-term investments that have been in a continuous unrealized gain (loss) position for less than one year.

Our non-governmental debt securities primarily consist of commercial paper and certificates of deposit. Our treasury and federal agencies primarily consist of U.S. Treasury bills and federal home loan debt securities. We do not intend to sell our investments in these securities prior to maturity and it is not likely that we will be required to sell these investments before recovery of the amortized cost basis.

A schedule of available-for-sale investments segregated by their original stated terms to maturity as of December 31, 2019 and 2018 are as follows (dollars in thousands):

Less than

one year

One to

five years

Six to

ten years

Greater

than ten

years

Total

Original stated term to maturity of available-for-sale-

investments as of December 31, 2019

125,087

59,751

650

185,488

Original stated term to maturity of available-for-sale-

investments as of December 31, 2018

156,657

38,845

926

196,428

Realized gains or losses resulting from sales of investments during the years ended December 31, 2019, 2018 and 2017 were not significant.

FASB ASC Topic 820 – Fair Value Measurements establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

As of December 31, 2019 and 2018, we held investments that are required to be measured at fair value on a recurring basis. These investments (available-for-sale) consist of municipal bonds, non-governmental debt securities and treasury and federal agencies securities. Available for sale securities included in Level 1 are valued at quoted prices in active markets for identical assets and liabilities. Available for sale securities included in Level 2 are estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, such as quoted prices for identical or similar assets or liabilities in inactive markets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Investments measured at fair value on a recurring basis subject to the disclosure requirements of FASB ASC Topic 820 – Fair Value Measurements at December 31, 2019 and 2018 were as follows (dollars in thousands):

	As of December 31, 2019
	Level 1		Level 2		Level 3		Total
Municipal bonds	$	-	$	1,364	$	-	$	1,364
Non-governmental debt securities		-		165,819		-		165,819
Treasury and federal agencies		-		18,305		-		18,305
Totals	$	-	$	185,488	$	-	$	185,488

	As of December 31, 2018
	Level 1		Level 2		Level 3		Total
Non-governmental debt securities	$	20,000	$	159,091	$	-	$	179,091
Treasury and federal agencies		-		17,337		-		17,337
Totals	$	20,000	$	176,428	$	-	$	196,428

Our investment in an equity affiliate, which is recorded within other noncurrent assets on our consolidated balance sheets, represents an international investment in a private company. As of December 31, 2019, our investment in an equity affiliate equated to a 30.7%, or $2.7 million, non-controlling interest in CCKF, a Dublin-based educational technology company providing intelligent systems to power the delivery of individualized and personalized learning.

For the year ended December 31, 2019 we recorded approximately $0.1 million of gain and for the years ended December 31, 2018 and 2017, we recorded approximately $0.4 million and $0.3 million of loss, respectively, related to our proportionate investment in CCKF within miscellaneous income on our consolidated statements of income (loss) and comprehensive income (loss).

We make periodic operating maintenance payments related to proprietary rights that we use in our intellipath^® personalized learning technology. The total fees recorded for the years ended December 31, 2019, 2018 and 2017 were as follows (dollars in thousands):