Condensed Balance Sheets - USD ($)	Jun. 30, 2026	Dec. 31, 2025
Current assets
Cash and cash equivalents	$ 4,960,000	$ 6,811,000
Restricted cash	94,000	94,000
Deferred offering costs	507,000	634,000
Prepaid expenses and other current assets	227,000	567,000
TOTAL ASSETS	5,788,000	8,106,000
Current liabilities
Accounts payable	1,016,000	748,000
Accrued expenses	1,203,000	1,560,000
Warrant liability		11,000
Total Current Liabilities	2,219,000	2,319,000
Stockholders’ Equity
Preferred stock value	1,000	1,000
Common stock, par value $0.001, 250,000,000 shares authorized, 44,668,969 and 25,534,173 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively	45,000	26,000
Additional paid in capital	734,952,000	729,661,000
Accumulated deficit	(731,429,000)	(723,901,000)
Total Stockholders’ Equity	3,569,000	5,787,000
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	5,788,000	8,106,000
Series L Preferred Stock [Member]
Stockholders’ Equity
Preferred stock value

Warrant liability current.

No definition available.

Name:	GTBP_WarrantLiabilityCurrent
Namespace Prefix:	GTBP_
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).