Note 6 - Convertible Senior Notes (Details Textual)	3 Months Ended
Mar. 31, 2023 USD ($) $ / shares	Mar. 31, 2022 USD ($)	Dec. 31, 2022 $ / shares
Proceeds from Convertible Debt	$ 393,518,000	$ 0
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares	$ 0.001		$ 0.001
Debt Issuance Costs, Net	$ 3,263
March 2023 Note [Member] \| Convertible Senior Notes [Member]
Debt Instrument, Face Amount	$ 402,500,000
Debt Instrument, Interest Rate, Stated Percentage	3.00%
Proceeds from Convertible Debt	$ 391,492,000
Debt Instrument, Convertible, Conversion Ratio	14.3516
Debt Instrument, Convertible, Conversion Price (in dollars per share) \| $ / shares	$ 69.68
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger	130.00%
Debt Instrument, Convertible, Threshold Trading Days	20
Debt Instrument, Convertible, Threshold Consecutive Trading Days	30
Debt Instrument, Redemption Price, Percentage	100.00%
Debt Instrument, Interest Rate, Effective Percentage	3.59%
Debt Issuance Costs, Net	$ 11,008,000
March 2023 Note [Member] \| Convertible Senior Notes [Member] \| Minimum [Member]
Debt Instrument, Redemption, Minimum Aggregate Principal Outstanding	$ 100,000,000

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Face amount or stated value per share of common stock.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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