Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2013 Case Lawsuit	Sep. 30, 2011 Case	Dec. 31, 2014 Lawsuit	Dec. 31, 2013 Lawsuit	Dec. 31, 2012
Loss Contingencies [Line Items]
Rent expense under operating lease			$ 900,000	$ 800,000	$ 900,000
Capital lease obligations, noncurrent	67,000		29,000	67,000
Open purchase order			19,100,000
Number of lawsuits against Company			12
Number of active product liability cases	12	55
Number of new lawsuits	2			2
Litigation recovery			0	(1,450,000)	2,200,000
Amount payable on termination of contract			1,000,000
Severance costs			500,000
2008
Loss Contingencies [Line Items]
Remaining Insurance Coverage			0
Office Equipment
Loss Contingencies [Line Items]
Capital lease obligation			61,000
Original cost of leased equipment			147,000
Associated accumulated amortization			86,000
Capital lease obligations, noncurrent			$ 67,000
Interest rate			6.20%