Liquidity (Narrative) (Details)							12 Months Ended
	Feb. 09, 2022 USD ($) tranche $ / shares shares	Oct. 28, 2021 USD ($) $ / shares shares	Jan. 26, 2021 $ / shares shares	Mar. 27, 2020 USD ($) $ / shares shares	Feb. 12, 2020 USD ($) shares	Jan. 27, 2020 $ / shares shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares
Cash and cash equivalents | $							$ 10,288,000	$ 9,649,000
Liquidity, management evaluation							The Company has prepared its consolidated financial statements on a going concern basis, which assumes that the Company will realize its assets and satisfy its liabilities in the normal course of business. However, the Company has incurred net losses since its inception and has negative operating cash flows. These circumstances raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from the outcome of the uncertainty concerning the Company’s ability to continue as a going concern.
Proceeds from issuance of private placement | $	$ 45,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01					$ 0.01	$ 0.01
Securities Purchase Agreement [Member]
Proceeds from equity offerings, gross | $		$ 7,000,000.0
Shares Issued, Price Per Share | $ / shares		$ 3.30
Proceeds from issuance of private placement | $				$ 25,000,000.0
Number of common warrants sold per share of common stock				1
Securities Purchase Agreement [Member] | Cystic Fibrosis Foundation [Member]
Stock Issued During Period, Shares, New Issues		909,091
Securities Purchase Agreement [Member] | Innoviva Strategic Opportunities LLC [Member]
Securities purchase agreement maximum gross proceeds | $	$ 45,000,000
Number of tranches | tranche	2
Shares Issued, Price Per Share | $ / shares	$ 5.00
Stock Issued During Period, Shares, New Issues	9,000,000	1,212,122
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	4,500,000
Exercise price of warrants | $ / shares	$ 5.00
Securities Purchase Agreement [Member] | Common Stock Subject to Mandatory Redemption [Member]
Shares Issued, Price Per Share | $ / shares			$ 3.25	$ 2.87		$ 2.87
Stock Issued During Period, Shares, New Issues			6,153,847	8,710,800		8,710,800
Exercise price of warrants | $ / shares			$ 3.25
Securities Purchase Agreement [Member] | Warrants and Rights Subject to Mandatory Redemption [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				8,710,800		8,710,800
Exercise price of warrants | $ / shares						$ 2.87
Securities Purchase Agreement [Member] | Warrants and Rights Subject to Mandatory Redemption [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			6,153,847
Securities Purchase Agreement First Tranche [Member]
Stock Issued During Period, Shares, New Issues					993,139
Proceeds from issuance of private placement | $					$ 2,800,000
Securities Purchase Agreement First Tranche [Member] | Innoviva Strategic Opportunities LLC [Member]
Stock Issued During Period, Shares, New Issues	3,614,792
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	1,807,396
Net proceeds from issuance of common stock and warrants | $	$ 18,100,000
Securities Purchase Agreement Second Tranche [Member]
Stock Issued During Period, Shares, New Issues				7,717,661
Proceeds from issuance of private placement | $				$ 22,200,000
Securities Purchase Agreement Second Tranche [Member] | Innoviva Strategic Opportunities LLC [Member]
Stock Issued During Period, Shares, New Issues	5,385,208
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,692,604
Net proceeds from issuance of common stock and warrants | $	$ 26,900,000