Debt - Long-Term Debt from Royalty-Bearing Instrument-December 2012 Financing - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended
	Dec. 06, 2012	May 31, 2020	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Debt Disclosure [Line Items]
Long-term debt from royalty-bearing instrument, carrying amount net of unamortized discount			$ 36,660,000		$ 49,702,000
Interest expense, non-cash			289,000	$ 446,000
CPPIB
Debt Disclosure [Line Items]
Maximum repayment of future revenue and receivables			38,200,000
Repayment under agreement			$ 14,200,000
CPPIB | Scenario Forecast
Debt Disclosure [Line Items]
Repayment under agreement		$ 15,200,000
Vascepa | CPPIB
Debt Disclosure [Line Items]
Debt and future repayments percentage of net revenues			10.00%
BioPharma Debt
Debt Disclosure [Line Items]
Amount received at the closing of the agreement	$ 100,000,000.0
Maximum repayment of future revenue and receivables	$ 150,000,000.0
Royalty-Bearing Debt
Debt Disclosure [Line Items]
Gain (loss) on change in fair value of derivative liabilities			$ 0	0
Long-term debt from royalty-bearing instrument, carrying amount net of unamortized discount			36,700,000		$ 49,700,000
Royalty-Bearing Debt | Cash
Debt Disclosure [Line Items]
Interest expense, contractual coupon interest			800,000	1,200,000
Royalty-Bearing Debt | Non Cash
Debt Disclosure [Line Items]
Interest expense, non-cash			$ 300,000	$ 400,000