Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($) Segment Customer	Mar. 31, 2020 USD ($)
Significant Accounting Policies [Line Items]
Trade receivables, credit period	30 days
Maturities period	24 months
Unrealized gain (loss) on held-to-maturity securities | $	$ 0.2	$ (0.7)
Number of operating segments | Segment	1
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect [true false]	true
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201912Member
Short Term Investments
Significant Accounting Policies [Line Items]
Maturities period	12 months
Long Term Investments
Significant Accounting Policies [Line Items]
Maturities period	12 months
Money Market Instruments
Significant Accounting Policies [Line Items]
Maturities period	90 days
Gross Product Sales | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Number of customers | Customer	3
Customer A | Gross Product Sales | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	27.00%	24.00%
Customer A | Accounts Receivable | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	35.00%	32.00%
Customer B | Gross Product Sales | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	35.00%	35.00%
Customer B | Accounts Receivable | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	36.00%	27.00%
Customer C | Gross Product Sales | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	31.00%	32.00%
Customer C | Accounts Receivable | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	24.00%	30.00%
Internal Revenue Service (IRS)
Significant Accounting Policies [Line Items]
Open tax year	2018
Earliest Tax Year | New Jersey Department of Treasury
Significant Accounting Policies [Line Items]
Open tax year	2012
Latest Tax Year | New Jersey Department of Treasury
Significant Accounting Policies [Line Items]
Open tax year	2015