Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 9,615	$ 15,294
Short-term investments	36,496	22,276
Prepaid expenses and other current assets	880	1,345
Total current assets	46,991	38,915
Right-of-use asset	1,274
Other assets	264	254
Total assets	48,529	39,169
Current liabilities:
Accounts payable	1,390	1,408
Accrued expenses	2,512	2,763
Current portion of operating lease liabilities	1,266
Total current liabilities	5,168	4,171
Other long-term liabilities		56
Total liabilities	5,168	4,227
Commitments (Note 6)
Stockholders' equity:
Preferred stock, $0.001 par value per share, 5,000,000 shares authorized and no shares issued and outstanding
Common stock, $0.001 par value per share, 150,000,000 shares authorized; 11,553,937 and 7,141,996 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	12	7
Additional paid-in capital	253,821	232,243
Accumulated other comprehensive income (loss)	1	(4)
Accumulated deficit	(210,473)	(197,304)
Total stockholders' equity	43,361	34,942
Total liabilities and stockholders' equity	$ 48,529	$ 39,169

Amount of lessee's right to use underlying asset under operating lease, non-current.

No definition available.

Name:	catb_OperatingLeaseRightOfUseAssetNonCurrent
Namespace Prefix:	catb_
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).