Note H - Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial liabilities measured at fair value on recurring basis	$ 1,686	$ 2,118
Financial assets measured at fair value on recurring basis		3,260
Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis		246
US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis		3,014
Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Financial assets measured at fair value on recurring basis		3,260
Fair Value, Inputs, Level 1 [Member] | Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis		246
Fair Value, Inputs, Level 1 [Member] | US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis		3,014
Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis	249	273
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	1,437	1,845
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member] | Certificates of Deposit [Member]
Financial assets measured at fair value on recurring basis
Fair Value, Inputs, Level 3 [Member] | US Treasury Securities [Member]
Financial assets measured at fair value on recurring basis
Deerfield Warrant Liability [Member]
Financial liabilities measured at fair value on recurring basis	1,211	1,557
Deerfield Warrant Liability [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Deerfield Warrant Liability [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Deerfield Warrant Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	1,211	1,557
Embedded Put Option [Member]
Financial liabilities measured at fair value on recurring basis	212	154
Embedded Put Option [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Put Option [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Put Option [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	212	154
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member]
Financial liabilities measured at fair value on recurring basis
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Fundamental Change and Make-Whole Interest Provisions Embedded in 2021 Notes [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Deerfield Note Put Option [Member]
Financial liabilities measured at fair value on recurring basis	14	134
Embedded Deerfield Note Put Option [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Deerfield Note Put Option [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis
Embedded Deerfield Note Put Option [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis	14	134
KVK Warrant Liability [Member]
Financial liabilities measured at fair value on recurring basis	249	273
KVK Warrant Liability [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities measured at fair value on recurring basis
KVK Warrant Liability [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities measured at fair value on recurring basis	249	273
KVK Warrant Liability [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities measured at fair value on recurring basis