Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes And Tax Related [Line Items]
Impact of rate change on deferred taxes	$ 45,100,000	$ 45,129,000	$ (383,000)	$ 749,000
Tax on unrepatriated foreign earnings	0	0
Valuation allowance	(141,100,000)	(141,094,000)
Deferred tax asset, valuation allowance	5,368,000	$ 5,368,000	140,915,000	154,252,000	$ 152,138,000
Examination period of income tax returns		3 years
Write-off of foreign tax and research credits		$ 0	7,125,000	0
Unrecognized tax benefits	9,866,000	9,866,000	10,441,000		$ 11,450,000	$ 12,144,000
Reductions related to prior year tax positions		(506,000)	0	0
Total liabilities for tax obligation and associated interest and penalties	37,000,000	37,000,000	34,400,000
Income tax provisions for uncertain tax benefits	9,900,000	9,900,000	10,400,000
Interest accruals	24,900,000	24,900,000	21,900,000
Penalty accruals	2,200,000	2,200,000	2,100,000
Other tax long-term liabilities	36,300,000	36,300,000	33,200,000
Uncertain tax positions		3,128,000	1,529,000	2,523,000
Total noncurrent assets related to indemnification	26,300,000	26,300,000	17,900,000
Tax indemnification income		8,367,000	1,055,000	1,655,000
Federal
Income Taxes And Tax Related [Line Items]
Net operating loss carryovers	233,500,000	233,500,000
Tax indemnification income		6,500,000
State Research Credit
Income Taxes And Tax Related [Line Items]
Tax credits	2,600,000	2,600,000
Massachusetts | Investment Tax Credits
Income Taxes And Tax Related [Line Items]
Tax credits	1,100,000	1,100,000
Net operating loss carryovers without expiration date	400,000	$ 400,000
Minimum | State and Local Jurisdiction
Income Taxes And Tax Related [Line Items]
Examination period of income tax returns		3 years
Minimum | Federal
Income Taxes And Tax Related [Line Items]
Operating loss carryovers, year of expiration		2030
Minimum | State Research Credit
Income Taxes And Tax Related [Line Items]
Tax credit carryforward, year of expiration		2024
Maximum | State and Local Jurisdiction
Income Taxes And Tax Related [Line Items]
Examination period of income tax returns		4 years
Maximum | Federal
Income Taxes And Tax Related [Line Items]
Operating loss carryovers, year of expiration		2037
Maximum | State Research Credit
Income Taxes And Tax Related [Line Items]
Tax credit carryforward, year of expiration		2032
BMS
Income Taxes And Tax Related [Line Items]
Payments for state income tax settlements		$ 0	700,000	1,900,000
Decrease in amount due from BMS included within other long-term assets		8,400,000	1,300,000	$ 1,600,000
Deferred Tax Assets
Income Taxes And Tax Related [Line Items]
Penalty accruals	$ 700,000	$ 700,000	$ 1,200,000