XML 41 R28.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Marketable Securities (Tables) | 3 Months Ended
--- | ---
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract] |
Summary of amortized cost and fair value | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | ​ |  | Gross |  | Gross |  | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | ​
​ | ​ | Cost | ​ | Losses | ​ | Gains | ​ | Fair Value
December 31, 2023: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
U.S. Treasury securities and obligations of U.S. government agencies |  | $ | 148,119 | ​ | $ | (1,200) | ​ | $ | — |  | $ | 146,919
Bank certificates of deposit | ​ | ​ | 7,842 | ​ | ​ | (94) | ​ | ​ | — | ​ | ​ | 7,748
Corporate securities | ​ | ​ | 190,696 | ​ | ​ | (2,189) | ​ | ​ | — | ​ | ​ | 188,507
​ | ​ | $ | 346,657 | ​ | $ | (3,483) | ​ | $ | — | ​ | $ | 343,174
September 30, 2023: | ​ | ​ |  | ​ |  |  | ​ |  |  | ​ |  |
U.S. Treasury securities and obligations of U.S. government agencies | ​ | $ | 227,804 |  | $ | (2,573) |  | $ | — | ​ | $ | 225,231
Bank certificates of deposit | ​ | ​ | 8,122 | ​ | ​ | (170) | ​ | ​ | — | ​ | ​ | 7,952
Corporate securities | ​ | ​ | 221,155 | ​ | ​ | (4,127) | ​ | ​ | — | ​ | ​ | 217,028
​ | ​ | $ | 457,081 | ​ | $ | (6,870) | ​ | $ | — | ​ | $ | 450,211
Schedule of fair values of marketable securities by contractual maturities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Amortized | ​ | ​ | ​
​ | ​ | Cost | ​ | ​ | Fair Value
Due in one year or less | ​ | $ | 283,849 | ​ | $ | 281,212
Due after one year through five years | ​ |  | 59,486 | ​ |  | 58,640
Due after five years through ten years | ​ | ​ | — | ​ | ​ | —
Due after ten years | ​ |  | 3,322 | ​ |  | 3,322
Total marketable securities | ​ | $ | 346,657 | ​ | $ | 343,174

X
- Definition Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments. + References No definition available. + Details
Name: | us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration