Consolidated Financial Statement Components - Depreciation, Amortization and Accretion (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Property, Plant and Equipment [Line Items]
Total depreciation	$ 701	$ 1,040	$ 1,465	$ 2,162
Amortization
Intangible assets	0	0	0	417
Capitalized software development costs	0	1,263	0	2,297
Total amortization	0	1,263	0	2,714
Accretion	170	154	340	308
Total depreciation, amortization and accretion expense	871	2,457	1,805	5,184
Leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation	16	18	35	34
Asset retirement costs
Property, Plant and Equipment [Line Items]
Asset retirement costs	(175)	(22)	(350)	(44)
Paging and computer equipment
Property, Plant and Equipment [Line Items]
Depreciation	800	982	1,650	2,052
Furniture, fixtures and vehicles
Property, Plant and Equipment [Line Items]
Depreciation	$ 60	$ 62	$ 130	$ 120

Depreciation, Asset Retirement Costs

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Depreciation, Net Of Asset Retirement Costs

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The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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Amount of expense for amortization of capitalized computer software costs.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.

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