Revenue Recognition - Summary of Product Revenue Allowance and Reserve Categories (Detail) - HEPLISAV-B® $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Product Revenue Allowance and Revenue Categories [Line Items]
Balance at December 31, 2018	$ 2,305
Provision related to current period sales	3,538
Credit or payments made during the period	(1,744)
Balance at March 31, 2019	4,099
Chargebacks, distribution fees, discounts and other fees
Product Revenue Allowance and Revenue Categories [Line Items]
Balance at December 31, 2018	1,736
Provision related to current period sales	3,080
Credit or payments made during the period	(1,658)
Balance at March 31, 2019	3,158
Returns
Product Revenue Allowance and Revenue Categories [Line Items]
Balance at December 31, 2018	569
Provision related to current period sales	458
Credit or payments made during the period	(86)
Balance at March 31, 2019	$ 941