Commitments and Contingencies - Additional Information (Detail) (USD $)	Mar. 31, 2013
Commitment And Contingencies [Line Items]
Future minimum lease obligations, for the year ended December 31, 2013	$ 806,000
Future minimum lease obligations, for the year ended December 31, 2014	659,000
Future minimum lease obligations, for the year ended December 31, 2015	192,000
Future minimum lease obligations, for the year ended December 31, 2016 and thereafter	0
Change in control, if occurs, may require severance benefits payable	714,000
Purchase commitments pending	$ 12,900,000