Convertible Senior Notes and Capped Call Transactions - Schedule of Convertible Notes (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Net carrying amount	$ 223,584	$ 218,460
2025 Senior Notes
Debt Instrument [Line Items]
Principal	253,000
Unamortized discount	(24,196)
Unamortized issuance costs	(5,220)
Net carrying amount	223,584
Equity component, net of discount and issuance costs	$ 30,794

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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Amount, after accumulated amortization, of debt discount.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Debt Instrument, Face Amount Including Additional Purchases from Exercised Options

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