Description of Business and Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) investment_type inventory_category numberOfClassesOfReceivables	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2021 USD ($)	Apr. 01, 2020 shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Employee retention credit, CARES Act	$ 1,348,000
Material classes of receivables | numberOfClassesOfReceivables	2
Number of types of investments | investment_type	2
Other than temporary impairment losses, investments	$ (1,919,000)
Number of inventory categories | inventory_category	3
Real estate rental period	30 days
Common stock issued upon conversion (in shares) | shares					2,622,177
Intangible assets, useful life	10 years
Goodwill	$ 9,186,000	$ 9,186,000
Lessee, finance lease, term of contract	4 years
Advertising costs	$ 42,919,000	62,536,000	$ 33,457,000
Advertising production costs	256,000	2,029,000	$ 1,644,000
Accumulated deficit	$ (270,313,000)	$ (251,786,000)
Subsequent Event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit				$ (262,551,000)
Restatement Adjustment | Subsequent Event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit				$ 7,762,000
COVID-19
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of positions eliminated	400
Number of positions placed on furlough	1,000
Restructuring costs	$ 7,864,000
1.75% Convertible Senior Notes due 2023
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt conversion, original debt, amount	$ 1,849,000
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful Lives (years)	2 years
Property, plant and equipment, estimated useful lives	two years
Operating lease term	1 year
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Useful Lives (years)	3 years
Operating lease term	11 years