Business and Summary of Significant Accounting Policies (Details)			12 Months Ended
	Dec. 17, 2020 USD ($)	Dec. 31, 2019 $ / shares	Dec. 31, 2022 USD ($) segment $ / shares	Dec. 31, 2021 USD ($) $ / shares	Jan. 20, 2021 USD ($)
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Cash and cash equivalents			$ 11,531,000	$ 25,990,000
Loss from continuing operations			80,145,000	54,244,000
Accumulated deficit			546,054,000	515,969,000
Foreign currency re-measurement loss			$ 100,000	400,000
Number of operating segments | segment			1
Number of reportable segments | segment			1
Capitalized contract cost, amortization period			5 years
Asset impairment charges			$ 0	0
Advertising expense			$ 1,200,000	$ 1,000,000
Minimum
Related Party Transaction [Line Items]
Revenue, performance obligation, duration			1 year
Property, and equipment, useful life			3 years
Maximum
Related Party Transaction [Line Items]
Revenue, performance obligation, duration			3 years
Property, and equipment, useful life			7 years
Revolving Credit Facility | Line of Credit
Related Party Transaction [Line Items]
Line of credit facility, remaining borrowing capacity			$ 3,500,000
Brainspace
Related Party Transaction [Line Items]
Ownership percentage sold	100.00%
Consideration for sale of discontinued operation	$ 125,000,000				$ 125,000,000
Cyxtera Technologies, Inc.
Related Party Transaction [Line Items]
Partial share redeemed, cancelled, and retired		0.04
Common stock, par value (in dollars per share) | $ / shares		$ 0.01