Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Current assets:
Cash and cash equivalents	$ 90,693	$ 31,374
Marketable securities	0	23,362
Prepaid expenses and other current assets	4,076	6,517
Total current assets	94,769	61,253
Property and equipment, net	0	23
Operating lease right-of-use assets	0	175
Other assets, noncurrent	810	810
Total assets	95,579	62,261
Current liabilities:
Accounts payable	7	126
Accrued expenses and other current liabilities	1,927	3,791
Income tax liabilities	1,349	0
Operating lease liabilities	0	94
Deferred revenue	0	212
Total current liabilities	3,283	4,223
Operating lease liabilities, noncurrent	0	82
Total liabilities	3,283	4,305
Commitments and contingencies (Note 7)
Stockholders' equity
Common stock, $0.0001 par value per share; 200,000,000 shares authorized as of September 30, 2026 and December 31, 2025; and 5,333,190 and 5,283,321 shares issued and outstanding as of September 30, 2026 and December 31, 2025, respectively	4	4
Preferred stock, $0.0001 par value per share; 50,000,000 shares authorized as of September 30, 2026 and December 31, 2025; no shares issued or outstanding as of September 30, 2026 and December 31, 2025	0	0
Additional paid-in capital	361,628	359,932
Accumulated other comprehensive gain	0	18
Accumulated deficit	(269,336)	(301,998)
Total stockholders' equity	92,296	57,956
Total liabilities and stockholders' equity	$ 95,579	$ 62,261

Accrued Expenses And Other Liabilities, Current

No definition available.

Name:	rlyb_AccruedExpensesAndOtherLiabilitiesCurrent
Namespace Prefix:	rlyb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).