Consolidated Balance Sheet - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Construction in Progress, Gross	[1]	$ 6,707	$ 12,906
Depreciation		7,300	5,200	$ 4,200
Waltham And Marlborough [Member]
Construction in Progress, Gross		4,200
Waltham And Marlboro [Member]
Construction in Progress, Gross		1,100
Rancho Dominguez [Member]
Construction in Progress, Gross		600
Marlborough facility [Member]
Construction in Progress, Gross			7,300
Software Development [Member]
Construction in Progress, Gross			2,100
Casting Machine [Member]
Construction in Progress, Gross		$ 400	$ 2,100

[1] Construction in progress as of December 31, 2019 primarily includes $4.2 million for the buildout of our Waltham and Marlborough, Massachusetts facilities, $1.1 million of other manufacturing improvements in Waltham and Marlboro and $0.6 million in manufacturing improvements at our Rancho Dominguez, California facility. Construction in progress as of December 31, 2018 includes $7.3 million for the buildout of our Marlborough facility, $2.1 million in capitalized internal-use software development costs and $2.1 million for a casting machine, among other projects.