Note 4 - Fair Value Measurements - Contingent Consideration Liabilities (Details) - Molecular Insight Pharmaceuticals, Inc. [Member] $ in Millions	Sep. 30, 2017 USD ($)
Milestone Payment upon First Commercial Sale [Member]
Contingent Consideration	$ 23
Milestone Payment upon Achievement of Net Sales Level 1 [Member]
Contingent Consideration	5
Milestone Payment upon Achievement of Net Sales Level 2 [Member]
Contingent Consideration	5
Milestone Payment upon Achievement of Net Sales Level 3 [Member]
Contingent Consideration	10
Milestone Payment upon Achievement of Net Sales Level 4 [Member]
Contingent Consideration	20
Milestone Payment upon Achievement of Net Sales Level 5 [Member]
Contingent Consideration	30
Milestone Payment upon Achievement of All Levels of Net Sales [Member]
Contingent Consideration	70
AZEDRA Program [Member] | Milestone Payment upon First Commercial Sale [Member]
Contingent Consideration	8
The 1404 Program [Member] | Milestone Payment upon First Commercial Sale [Member]
Contingent Consideration	10
The 1095 Program[Member] | Milestone Payment upon First Commercial Sale [Member]
Contingent Consideration	$ 5