Long-Term Debt - Schedule of Interest Expense Related to Notes (Details) - 3.00% Convertible Senior Notes Due 2025 - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 1,322	$ 1,322
Amortization of debt discount	924	868
Amortization of issuance costs	232	218
Total interest expense related to the Notes	$ 2,478	$ 2,408

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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