Commitments and Contingencies - Narrative (Details) - USD ($)			3 Months Ended				9 Months Ended
	Jun. 22, 2020	Feb. 06, 2019	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Commitments [Line Items]
Rent expense			$ 300,000			$ 300,000	$ 900,000	$ 900,000
Purchase commitments related to inventory			400,000		$ 400,000		400,000
Accrued litigation expense			0		3,200,000		0
Eric B Fromer Chiropractic Inc, class action
Other Commitments [Line Items]
Litigation expense					700,000	$ 2,500,000
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 | Eric B Fromer Chiropractic Inc, class action
Other Commitments [Line Items]
Damages sought per violation		$ 500
Treble damages sought per violation of TCPA | Eric B Fromer Chiropractic Inc, class action
Other Commitments [Line Items]
Damages sought per violation		$ 1,500
Indemnification Agreement
Other Commitments [Line Items]
Costs to defend lawsuits or settle claims							0
Costs accrued to defend lawsuits			$ 0				$ 0