Accrued Liabilities - Accrued Severance and Restructuring Balances (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Payables and Accruals [Abstract]
Severance costs, Beginning Balance	$ 2,593	$ 1,953
Severance costs, Charges	965	1,751
Severance costs, Cash Paid	(2,084)	(1,111)
Severance costs, Ending Balance	1,474	2,593
Restructuring costs, Beginning Balance	0	0
Restructuring costs, Charges	18	7
Restructuring costs, Cash Paid	(18)	(7)
Restructuring costs, Ending Balance	0	0
Total accrued severance and restructuring costs, Beginning Balance	2,593	1,953
Total accrued severance and restructuring costs, Charges	983	1,758
Total accrued severance and restructuring costs, Cash Paid	(2,102)	(1,118)
Total accrued severance and restructuring costs, Ending Balance	$ 1,474	$ 2,593