Commitments and Contingencies - Narrative (Details) - USD ($)			12 Months Ended
	Jun. 22, 2020	Feb. 06, 2019	Dec. 31, 2020	Dec. 31, 2019
Operating Leased Assets [Line Items]
Rent expense			$ 1,200,000	$ 1,200,000
Purchase commitments related to inventory			300,000	400,000
Accrued litigation expense			0	3,200,000
Class action Eric B. Fromer Chiropractic Inc.
Operating Leased Assets [Line Items]
Accrued litigation expense				$ 3,200,000
Settlement of approved claims by class members, fees, expenses and incentive awards	$ 2,600,000
Reversal of accrued litigation expense			600,000
Statutory damages sought per violation of TCPA | Class action Eric B. Fromer Chiropractic Inc.
Operating Leased Assets [Line Items]
Damages sought		$ 500
Treble damages sought per violation of TCPA | Class action Eric B. Fromer Chiropractic Inc.
Operating Leased Assets [Line Items]
Damages sought		$ 1,500
Indemnification Agreement
Operating Leased Assets [Line Items]
Costs to defend lawsuits or settle claims			0
Costs accrued to defend lawsuits			$ 0