CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 5,230	$ 8,289
Subscription receivable	0	635
Prepaid expenses and other current assets	717	1,077
Total current assets	5,947	10,001
Other assets	101	100
Total assets	6,048	10,101
Current liabilities:
Accounts payable	202	1,275
Accrued expenses	145	391
Total current liabilities	347	1,666
Royalty purchase liability	151,049	151,049
Warrant liability	0	1,055
Total liabilities	151,396	153,770
Commitments and contingencies (Note 10)
Stockholders' deficit:
Common stock, $0.001 par value: 200,000,000 shares authorized; 75,462,390 shares issued and outstanding at June 30, 2025 and December 31, 2024	75	75
Additional paid-in capital	311,010	308,247
Accumulated deficit	(459,030)	(456,363)
Total stockholders' deficit	(147,945)	(148,041)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	6,048	10,101
Series B Redeemable Convertible Preferred Stock [Member]
Stockholders' deficit:
Series B redeemable convertible preferred stock, $0.001 par value: 10,000,000 shares authorized; 119,318 shares issued and outstanding at June 30, 2025 and December 31, 2024	$ 2,597	$ 4,372

Subscription receivables

No definition available.

Name:	grtx_SubscriptionReceivables
Namespace Prefix:	grtx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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).