NOTE 3. INVESTMENTS

Our investments are classified as either available-for-sale or held-to-maturity. The following table summarizes available-for-sale and held-to-maturity investments as of March 31, 2018 and 2017 (in thousands):

	Available-for-Sale Investments
March 31, 2018	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)			Fair Value
Commercial paper	$	9,263	$	-	$	(12	)	$	9,251
Corporate bonds		66,868		-		(220	)		66,648
Municipal bonds		654		-		(4	)		650
Total available-for-sale investments	$	76,785	$	-	$	(236	)	$	76,549

	Held-to-Maturity Investments
March 31, 2018	Amortized Cost		Gross Unrecognized Gain		Gross Unrecognized (Loss)			Fair Value
Certificates of deposit	$	9,914	$	-	$	(22	)	$	9,892
Corporate bonds		52,938		-		(325	)		52,613
Municipal bonds		345		1		-			346
Total held-to-maturity investments	$	63,197	$	1	$	(347	)	$	62,851

	Available-for-Sale Investments
March 31, 2017	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)			Fair Value
Corporate bonds	$	6,381	$	-	$	(4	)	$	6,377
Municipal bonds		678		-		(16	)		662
Total available-for-sale investments	$	7,059	$	-	$	(20	)	$	7,039

	Held-to-Maturity Investments
March 31, 2017	Amortized Cost		Gross Unrecognized Gain		Gross Unrecognized (Loss)			Fair Value
Certificates of deposit	$	3,735	$	1	$	(1	)	$	3,735
Commercial paper		5,588		-		(3	)		5,585
Corporate bonds		57,009		-		(186	)		56,823
Municipal bonds		361		-		(1	)		360
Total held-to-maturity investments	$	66,693	$	1	$	(191	)	$	66,503

The amortized cost of our held-to-maturity investments approximates their fair value. As of March 31, 2018 and 2017, we did not have other-than-temporary impairment in the fair value of any individual security classified as held-to-maturity or available-for-sale. As of March 31, 2018 and 2017, we had unrealized losses on available-for-sale investments, net of related income taxes of $0.2 million and $12,000, respectively. Redemptions of investments in accordance with the callable provisions during fiscal 2018, 2017 and 2016 were $0.9 million, $0 and $0, respectively.

Redemptions of investments in accordance with the callable provisions during fiscal 2018, 2017 and 2016 were $0.9 million, $0 and $0, respectively. As of March 31, 2018 and 2017, we had unrealized losses on available-for-sale investments, net of related income taxes of $0.2 million and $12,000, respectively. The amortized cost of our held-to-maturity investments approximates their fair value.

The following table summarizes the amortized cost and fair value of our investments, classified by stated maturity as of March 31, 2018 and 2017 (in thousands):

	March 31, 2018				March 31, 2018
	Available-for-Sale Investments				Held-to-Maturity Investments
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than one year	$	70,625	$	70,429	$	50,077	$	49,902
Due in 1 to 3 years		6,160		6,120		13,120		12,949
Total investments	$	76,785	$	76,549	$	63,197	$	62,851

	March 31, 2017				March 31, 2017
	Available-for-Sale Investments				Held-to-Maturity Investments
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than one year	$	6,381	$	6,377	$	45,184	$	45,124
Due in 1 to 3 years		678		662		21,509		21,379
Total investments	$	7,059	$	7,039	$	66,693	$	66,503

The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of March 31, 2018 and 2017, aggregated by investment category and the length of time that individual securities have been in a continuous unrealized loss position (in thousands):

	As of March 31, 2018
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Certificates of deposit	$	8,899	$	(19	)	$	993	$	(3	)	$	9,892	$	(22	)
Commercial paper		9,251		(12	)		-		-			9,251		(12	)
Corporate bonds		98,173		(395	)		21,088		(150	)		119,261		(545	)
Municipal bonds		-		-			650		(4	)		650		(4	)
Total investments in an unrealized loss position	$	116,323	$	(426	)	$	22,731	$	(157	)	$	139,054	$	(583	)

	As of March 31, 2017
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Certificates of deposit	$	2,738	$	(1	)	$	-	$	-		$	2,738	$	(1	)
Commercial paper		2,989		(3	)		-		-			2,989		(3	)
Corporate bonds		44,387		(177	)		16,108		(13	)		60,495		(190	)
Municipal bonds		1,021		(17	)		-		-			1,021		(17	)
Total investments in an unrealized loss position	$	51,135	$	(198	)	$	16,108	$	(13	)	$	67,243	$	(211	)

We periodically review our investments for other-than-temporary impairment. We consider factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. For debt securities, we also consider whether (i) it is more likely than not that we will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During fiscal 2018, 2017 and 2016, we did not recognize any other-than-temporary impairment loss. As of March 31, 2018 and 2017, we did not have other-than-temporary impairment in the fair value of any individual security classified as held-to-maturity or available-for-sale.