Lease - Schedule of Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Cash paid for amounts included in measurement of lease liabilities:
Operating cash outflows - payments on operating leases	$ 4,107	$ 3,273
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 5,038	$ 2,716

Right of use assets obtained in exchange for new lease obligations abstract

No definition available.

Name:	ctkb_RightOfUseAssetsObtainedInExchangeForNewLeaseObligationsAbstract
Namespace Prefix:	ctkb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration