Accrued expenses and other current liabilities

12 Months Ended

Dec. 31, 2021

Payables And Accruals [Abstract]

Accrued expenses and other current liabilities

7. Accrued expenses and other current liabilities

Other accrued expenses and other current liabilities consisted of the following (in thousands):

	As of December 31,
	2021		2020
Payroll and related costs	$	13,764	$	11,179
Rebates		11,010		11,011
Sales returns and coupons		2,422		7,057
Selling and marketing expenses		2,850		228
Research and development expenses		1,995		925
Wholesale distributor fees		3,614		2,632
Professional fees		2,571		925
Operating lease liabilities		1,361		2,254
Other		4,717		1,959
Accrued expenses and other current liabilities	$	44,304	$	38,170

We expense advertising costs when incurred, which amounted to $39.7 million, $35.8 million and $9.0 million for 2021, 2020 and 2019, respectively.