NOTE 5. 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 September 30, 2017 and March 31, 2017 (in thousands).

	Available-for-Sale Investments
September 30, 2017	Amortized Cost		Gross Unrealized Gain		Gross Unrealized (Loss)			Fair Value
Commercial paper	$	7,472	$	-	$	(1	)	$	7,471
Corporate bonds		43,075		-		(50	)		43,025
Municipal bonds		666		-		(1	)		665
Total available-for-sale investments	$	51,213	$	-	$	(52	)	$	51,161

	Held-to-Maturity Investments
September 30, 2017	Amortized Cost		Gross Unrecognized Gain		Gross Unrecognized (Loss)			Fair Value
Certificates of deposit	$	15,890	$	1	$	(10	)	$	15,881
Commercial paper		4,988		-		(2	)		4,986
Corporate bonds		46,435		1		(166	)		46,270
Municipal bonds		354		-		(1	)		353
Total held-to-maturity investments	$	67,667	$	2	$	(179	)	$	67,490

	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

We did not have any redemption of investments in accordance with callable provisions during the three and six months ended September 30, 2017 and 2016. As of September 30, 2017 and March 31, 2017, we had unrealized loss on available-for-sale investments, net of related income taxes, of $32,000 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 September 30, 2017 and March 31, 2017 (in thousands).

	September 30, 2017				September 30, 2017
	Available-for-Sale Investments				Held-to-Maturity Investments
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than one year	$	45,668	$	45,638	$	44,239	$	44,172
Due in 1 to 3 years		5,545		5,523		23,428		23,318
Total investments	$	51,213	$	51,161	$	67,667	$	67,490

	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 September 30, 2017 and March 31, 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 September 30, 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	$	11,152	$	(10	)	$	-	$	-		$	11,152	$	(10	)
Commercial paper		12,457		(3	)		-		-			12,457		(3	)
Corporate bonds		68,858		(157	)		16,935		(59	)		85,793		(216	)
Municipal bonds		1,018		(2	)		-		-			1,018		(2	)
Total investments in an unrealized loss position	$	93,485	$	(172	)	$	16,935	$	(59	)	$	110,420	$	(231	)

	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 the three and six months ended September 30, 2017 and 2016, we did not recognize any other-than-temporary impairment loss. As of September 30, 2017 and March 31, 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.