Significant Accounting Policies (Narrative) (Details)			1 Months Ended	3 Months Ended			6 Months Ended	12 Months Ended		24 Months Ended
	Apr. 24, 2017 $ / shares shares	Nov. 22, 2016 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Apr. 23, 2017 shares	Jan. 01, 2017 USD ($)
Impairment of long-lived assets										$ 0
Goodwill impairment charge								$ 0	$ 7,600,000
Total market capitalization							$ 6,700,000
Reverse stock split, description								1-for-10 (1:10) reverse stock split of its common stock, par value $0.01 per share
Conversion ratio of reverse stock split	10
Common stock, par value (in dollars per share) | $ / shares	$ 0.01			$ 0.01		$ 0.01		$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized | shares	67,000,000			67,000,000		67,000,000		67,000,000	67,000,000	67,000,000	670,000,000
Increase in APIC and accumulated deficit resulting form newly adopted policy												$ 8,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Unrecognized tax benefits				$ 2,100,000				$ 2,100,000		$ 2,100,000
Australian Taxation Office [Member]
Tax rebates received					$ 2,000,000	$ 900,000
Public Offering of Warrants and Common Stock [Member]
Proceeds from equity offerings, gross		$ 4,000,000	$ 10,600,000
Staph Program [Member]
In-process resesarch and development							2,800,000		$ 5,200,000
Pseudomonas Program [Member]
In-process resesarch and development							1,900,000
In Process Research and Development [Member]
Impairment of in-process research and development				0			5,800,000		2,000,000
Income tax expense (benefit) relating to impairment charge							(1,300,000)		(400,000)
Patents [Member]
Finite-lived intangible assets, gross				493,000				493,000		493,000
Accumulated amortization				$ 217,000				$ 217,000		$ 217,000
Biocontrol Intellectual Property [Member]
In-process resesarch and development									7,300,000
In Process Research and Development [Member]
Impairment of in-process research and development							$ 5,800,000		$ 2,000,000