Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (2,959)	$ (3,280)
Adjustments to reconcile net loss to net cash (used in)/provided by operating activities
Depreciation and amortization	282	415
Amortization of operating lease right-of-use assets	92	5
Share-based compensation expenses	6,857	1,987
Provision for allowances for doubtful accounts	0	747
Loss on disposal of long-term investments	38	0
Deferred taxes	(40)	11
Change in fair value of warrant liabilities	(6,829)	(68)
Changes in operating assets and liabilities
Accounts receivable	(1,284)	(38)
Prepayment and deposit to suppliers	(980)	2,090
Due from related parties	0	28
Other current assets	8	(3)
Long-term deposits and prepayments	(554)	(750)
Accounts payable	403	(9)
Advance from customers	89	(362)
Accrued payroll and other accruals	197	57
Other current liabilities	(123)	326
Taxes payable	(49)	89
Lease payment liability related to short-term leases	(54)	43
Operating lease liabilities	(31)	(9)
Net cash (used in)/provided by operating activities	(5,331)	1,165
Cash flows from investing activities
Payment for leasehold improvements and purchase of vehicles, furniture and office equipment	(221)	0
Cash effect of deconsolidation of VIEs’ subsidiaries	(8)	0
Investments and advances to ownership investee entities	(463)	(27)
Short-term loan to an unrelated party	(312)	(944)
Repayment of short-term loan from an unrelated party	1,303	0
Payment for purchase of software technologies	(1,160)	0
Deposit and prepayment paid for contracts of other investing activities	(3,500)	0
Payment for blockchain platform applications development costs	0	(302)
Net cash used in investing activities	(4,361)	(1,273)
Cash flows from financing activities
Proceeds from issuance of common stock and warrant (net of cash offering cost of US$1,600)	17,111
Repayment of short-term bank loan	0	(427)
Net cash provided by/(used in) financing activities	17,111	(427)
Effect of exchange rate fluctuation on cash and cash equivalents	36	(13)
Net increase/(decrease) in cash and cash equivalents	7,455	(548)
Cash and cash equivalents at beginning of the period	4,297	1,603
Cash and cash equivalents at end of the period	11,752	1,055
Supplemental disclosure of cash flow information
Income taxes paid	0	0
Interest expense paid	$ 0	$ 2