Balance Sheet Account Detail - Summary of Other Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Supplies and deposits	$ 1,165	$ 185
Equity securities - CASI (see Note 10)	7,520	6,689
2018 Convertible Notes issuance costs (excluding current portion)	0	0
Executive officer life insurance – cash surrender value	9,651	9,181
Inventories - non-current portion	6,923	3,156
Other miscellaneous assets	45	0
Other assets	25,304	19,211
Gross unrealized losses	1,400
Accounting Standards Update 2015-03 [Member] | Long-term Debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	2,000	$ 2,200
Zevalin [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Supplies and deposits	$ 1,000