Subsequent events (Details) - Subsequent Event [Member] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Aug. 01, 2016
Subsequent Event [Line Items]
Percentage Of Outstanding Shares Distributed		100.00%
Record date for distribution	Jul. 22, 2016
Number of common stock distributed		20,230,000
Aptevo [Member]
Subsequent Event [Line Items]
Unsecured Debt - Aptevo Promissory Note		$ 20.0