Equity (Narrative) (Details)					9 Months Ended	12 Months Ended
	Dec. 20, 2018 USD ($) $ / shares shares	Nov. 09, 2017 USD ($) $ / shares shares	Feb. 14, 2017 $ / shares shares	Jan. 09, 2015 USD ($) shares	Sep. 30, 2013 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Jun. 19, 2019 shares	May 31, 2018 shares	Oct. 31, 2017 USD ($) shares	Mar. 31, 2017 USD ($) shares	Dec. 31, 2013 USD ($) $ / shares
Class Of Stock [Line Items]
Common stock, shares authorized						400,000,000	240,000,000		240,000,000			530,864
Common stock, shares issued						137,818,068	119,996,331
Common stock, value | $						$ 1,378,000	$ 1,200,000
Common stock closing price per share | $ / shares		$ 3.55
Shares sold at the market, value | $							$ 44,919,000	$ 5,560,000
Maximum [Member]
Class Of Stock [Line Items]
Common stock, preferred stock, warrants, debt securities and units issuable amount | $											$ 250,000,000
Celexion, LLC [Member]
Class Of Stock [Line Items]
Net proceeds from issuance of common stock | $		$ 550,000
Shares issued for purchased assets		999,317
Shares issued for purchased assets (in US$ per share) | $ / shares		$ 4.10
Stock Purchase Agreement [Member]
Class Of Stock [Line Items]
Net proceeds from issuance of common stock | $				$ 35,000,000
Shares sold at the market, shares	11,111,111			7,760,000
Number of shares purchased, price per share | $ / shares	$ 2.70
Stock purchase agreement, additional shares indisposable period	12 months
Stock purchase agreement, additional shares, favorable voting period	12 months
Shares sold at the market, value | $	$ 30,000,000
Percentage of common stock outstanding shares	8.50%
Maximum percentage of voting stock allowed to acquire	15.00%
Stock Purchase Agreement [Member] | Gilead Sciences Incorporation [Member]
Class Of Stock [Line Items]
Shares sold at the market, shares	11,110,000
Number of shares purchased, price per share | $ / shares	$ 2.70
Stock purchase agreement, additional shares indisposable period	12 months
Stock purchase agreement, additional shares, favorable voting period	12 months
Shares sold at the market, value | $	$ 30,000,000
Percentage of common stock outstanding shares	8.50%
Maximum percentage of voting stock allowed to acquire	15.00%
Stock Purchase Agreement [Member] | Incyte Corporation [Member]
Class Of Stock [Line Items]
Shares sold at the market, shares			10,000,000
Number of shares purchased, price per share | $ / shares			$ 6.00
Percentage of shares owned			18.10%
Stock purchase agreement, additional shares indisposable period			12 months
Stock purchase agreement, additional shares, favorable voting period			18 months
Stock purchase agreement, description			The parties also revised the existing standstill provision to permit Incyte’s acquisition of the Additional Shares, but Incyte was precluded from acquiring any additional shares of our voting stock until December 31, 2019.
Technology Transfer and License Agreement [Member]
Class Of Stock [Line Items]
Common stock, shares issued												373,351
Common stock, value | $												$ 1,500,000
Sales Agreement [Member] | At-The-Market Offerings [Member]
Class Of Stock [Line Items]
Common stock, shares authorized											15,000,000
At Market Issuance Sales Agreement [Member] | B. Riley FBR, Inc. [Member]
Class Of Stock [Line Items]
Shares sold at the market, shares						0
At Market Issuance Sales Agreement [Member] | Maximum [Member] | B. Riley FBR, Inc. [Member]
Class Of Stock [Line Items]
Common shares available for sale through sales agent										20,000,000
Common stock, additional shares reserved for sale							30,000,000
Registered direct offering [Member]
Class Of Stock [Line Items]
Shares sold in registered direct offering, shares					3,333,000
Warrants issued					1,000,000
Net proceeds from issuance of common stock | $					$ 9,500,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					0.3
Class of Warrant or Right, Exercisable Term					6 months
Class of Warrant or Right, Term					5 years
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares					$ 3.75
Series A convertible preferred stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Redemption Price Per Share | $ / shares													$ 94.86
Preferred Stock, Redemption Amount | $													$ 31,600,000
Preferred Stock, Liquidation Preference Per Share | $ / shares													$ 1,000
Series A-1 convertible preferred stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Amount of Preferred Dividends in Arrears | $						$ 1,400,000	$ 1,200,000
Preferred Stock, Per Share Amounts of Preferred Dividends in Arrears | $ / shares						$ 44.92	$ 38.33