Schedule of Provision on Discounts and Allowances by Category (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Disaggregation Of Revenue [Line Items]
Current period	$ 190
Balance at March 31, 2021	190
Chargebacks, Discounts for Prompt Pay and Other Allowances
Disaggregation Of Revenue [Line Items]
Current period	112
Balance at March 31, 2021	112
Rebates, Customer Fees / Credits and Co-Pay Assistance
Disaggregation Of Revenue [Line Items]
Current period	78
Balance at March 31, 2021	$ 78