FAIR VALUE MEASUREMENTS

6 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS

Cash, cash equivalents, and available-for-sale investments (in thousands):

	Amortized		Gross Unrealized		Gross Unrealized			Estimated		Cash and Cash		Short-Term		Long-Term
As of September 30, 2019	Costs		Gain		Loss			Fair Value		Equivalents		Investments		Investments
Cash	$	25,673	$	—	$	—		$	25,673	$	25,673	$	—	$	—
Level 1:
Money market funds	132,551		—		—			132,551		132,551		—		—
Treasury securities	6,578		7		(5		)	6,580		—		—		6,580
Subtotal	164,802		7		(5		)	164,804		158,224		—		6,580
Level 2:
Corporate bonds	37,858		123		(3		)	37,978		—		24,110		13,868
Commercial paper	5,592		—		—			5,592		3,995		1,597		—
Municipal securities	2,099		19		—			2,118		—		2,118		—
Agency bonds	1,499		—		—			1,499		—		1,499		—
Subtotal	47,048		142		(3		)	47,187		3,995		29,324		13,868
Total assets	$	211,850	$	149	$	(8	)	$	211,991	$	162,219	$	29,324	$	20,448

	Amortized		Gross Unrealized		Gross Unrealized			Estimated		Cash and Cash		Short-Term
As of March 31, 2019	Costs		Gain		Loss			Fair Value		Equivalents		Investments
Cash	$	25,364	$	—	$	—		$	25,364	$	25,364	$	—
Level 1:
Money market funds	251,219		—		—			251,219		251,219		—
Subtotal	276,583		—		—			276,583		276,583		—
Level 2:
Corporate debt	46,516		51		(29		)	46,538		—		46,538
Municipal securities	5,511		17		—			5,528		—		5,528
Asset backed securities	13,596		9		(17		)	13,588		—		13,588
Agency bonds	4,260		—		(15		)	4,245		—		4,245
Subtotal	69,883		77		(61		)	69,899		—		69,899
Total assets	$	346,466	$	77	$	(61	)	$	346,482	$	276,583	$	69,899

Historically, the Company had maintained all investments as short-term investments on its balance sheet, as the Company could liquidate these investments at any time and did not limit its liquidation of investments by contractual maturity date. Given the recent issuance of the convertible senior notes, and the associated increased cash, cash equivalents and investment balances, the Company expects to hold certain investments for at least 12 months from the reporting date and records these investments in long-term investments in accordance with the contractual maturity dates.

As of September 30, 2019, the estimated fair value of the Company's outstanding convertible senior notes (the Notes) was $302.7 million. The fair value of the Notes was determined based on the closing price for the Notes on the last trading day of the reporting period and is considered as Level 2 in the fair value hierarchy.