Additional information: condensed financial statements of the Company - Schedule of Condensed Statement of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from financing activities
Net (decrease)/increase in cash, cash equivalents and restricted cash	$ (31,988)	$ 45,788	$ (104,036)
Cash, cash equivalents, and restricted cash at beginning of year	165,448	122,930	233,479
Effect of exchange rates on cash and cash equivalents, and restricted cash	5,329	(3,270)	(6,513)
Cash, cash equivalents, and restricted cash at end of year	138,789	165,448	122,930
Xunlei Limited [Member]
Cash flows from operating activities
Net cash used in operating activities	(12,704)	(171,796)	(88,309)
Cash flows from investing activities
Net cash generated from investing activities	12,051	52,359	37,788
Cash flows from financing activities
Net cash used in financing activities	(4,475)
Net (decrease)/increase in cash, cash equivalents and restricted cash	(5,128)	(119,437)	(50,521)
Cash, cash equivalents, and restricted cash at beginning of year	110,238	229,675	280,196
Effect of exchange rates on cash and cash equivalents, and restricted cash	0	0	0
Cash, cash equivalents, and restricted cash at end of year	$ 105,110	$ 110,238	$ 229,675

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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