Available-For-Sale Securities (Tables)

12 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Interest-Bearing Investments in Available-for-Sale Securities

Available-for-sale securities consist of the following interest-bearing investments:


	As of September 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Corporate bonds	$	98,367	$	176	$	158	$	98,385
U.S. government treasuries		84,558		—		195		84,363
U.S. agency securities		60,794		—		148		60,646
Money market funds		52,504		—		—		52,504
Asset backed obligations		47,108		—		34		47,074
Commercial paper and certificates of deposit		33,448		—		—		33,448
Supranational and sovereign debt		8,819		—		42		8,777

Total(1)	$	385,598	$	176	$	577	$	385,197

(1)

Available-for-sale securities with maturities longer than 90 days from the date of acquisition were classified as short-term interest-bearing investments and available-for-sale securities with maturities of 90 days or less from the date of acquisition were included in cash and cash equivalents on the Company’s balance sheet. As of September 30, 2017, $329,997 of securities were classified as short-term interest-bearing investments and $55,200 of securities were classified as cash and cash equivalents.


	As of September 30, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Corporate bonds	$	95,852	$	339	$	37	$	96,154
U.S. government treasuries		105,377		151		15		105,513
U.S. agency securities		48,339		69		15		48,393
Money market funds		449,288		—		—		449,288
Asset backed obligations		30,121		73		—		30,194
Commercial paper and certificates of deposit		42,498		—		—		42,498
Supranational and sovereign debt		8,334		8		—		8,342

Total(2)	$	779,809	$	640	$	67	$	780,382

(2)

Available-for-sale securities with maturities longer than 90 days from the date of acquisition were classified as short-term interest-bearing investments and available-for-sale securities with maturities of 90 days or less from the date of acquisition were included in cash and cash equivalents on the Company’s balance sheet. As of September 30, 2016, $327,063 of securities were classified as short-term interest-bearing investments and $453,319 of securities were classified as cash and cash equivalents.

Available-for-Sale Securities Debt Maturities Market Value

As of September 30, 2017, the Company’s available-for-sale securities had the following maturity dates:


	Market Value
Due within one year	$	170,161
1 to 2 years		120,819
2 to 3 years		77,666
3 to 4 years		10,642
Thereafter		5,909

	$	385,197