Income Taxes - Significant components of deferred tax assets (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2021 CNY (¥)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 CNY (¥)
Deferred tax assets, net
Tax losses	¥ 42,139	$ 6,613	¥ 10,304
Depreciation	40	6	67
Accrued payroll expenses	754	118	1,572
Long-term investments impairment	1,620	254	2,700
Share of losses on equity method investments	525	82	794
Allowance for doubtful accounts	428	67	437
Less: valuation allowance	(18,554)	(2,911)	(9,667)
Deferred tax assets, net	¥ 26,952	$ 4,229	¥ 6,207

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from equity method investments.

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-Name Accounting Standards Codification
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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from property, plant, and equipment.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary difference from allowance for credit loss on accounts receivable.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from estimated impairment losses.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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