Note 6 - Convertible Senior Notes (Details Textual)	3 Months Ended			6 Months Ended
	Jun. 30, 2023 USD ($) $ / shares		Mar. 31, 2023 USD ($) $ / shares	Jun. 30, 2023 USD ($) $ / shares		Jun. 30, 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	$ 0.001			$ 0.001
Debt Issuance Costs, Net	$ 3,263			$ 3,263
Interest Costs Capitalized				181,000		$ 0
March 2023 Note [Member] | Convertible Senior Notes [Member]
Debt Instrument, Face Amount	$ 402,500,000		$ 402,500,000	$ 402,500,000
Debt Instrument, Interest Rate, Stated Percentage	3.00%	[1]	3.00%	3.00%	[1]
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
Unamortized Debt Issuance Expense	$ 10,618,000			$ 10,618,000
Interest Expense, Debt, Excluding Amortization	$ 3,010,000			$ 3,341,000
March 2023 Note [Member] | Convertible Senior Notes [Member] | Minimum [Member]
Debt Instrument, Redemption, Minimum Aggregate Principal Outstanding			$ 100,000,000

[1] The carrying amounts presented are net of unamortized debt issuance costs of $10,618 as of June 30, 2023.