Commitments and Contingencies - Additional Information (Detail)								12 Months Ended
	Jun. 30, 2015 ft²	Jan. 31, 2015 ft²	Apr. 30, 2014 ft²	Jan. 31, 2014 ft²	May 08, 2013 ft²	Dec. 15, 2012 ft²	Dec. 06, 2011 ft²	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 GBP (£)	Dec. 15, 2016 ft²	Nov. 01, 2013 USD ($) ft²	Nov. 01, 2013 EUR (€) ft²	Sep. 30, 2011 ft²	Jul. 01, 2011 ft²
Commitments and Contingencies Disclosure [Line Items]
Operating lease, rental expense | $								$ 600,000	$ 800,000	$ 1,000,000
Potential payable amount over the agreement terms based on minimum purchase obligation | $								$ 44,600,000
Dublin
Commitments and Contingencies Disclosure [Line Items]
Office space leased (in square feet)													270	270	320
Operating lease, expiration date								Oct. 31, 2017
Operating lease, renewal option								1 year
Operating lease, monthly rent													$ 3,100	€ 2,900
Bedminster
Commitments and Contingencies Disclosure [Line Items]
Office space leased (in square feet)												732				9,747
Operating lease, expiration date								Mar. 31, 2018
Additional office space leased (in square feet)					10,883	2,601	2,142
Square feet vacated in exchange for reduction on future rent payments			2,000	2,142
Sublease | Bedminster
Commitments and Contingencies Disclosure [Line Items]
Additional office space leased under sublease (in square feet)	2,500	4,700
Further Indication for AMR101 | Marketing Approval In Europe
Commitments and Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment								$ 9,300,000			£ 7,500,000
Further Indication for AMR101 | Potential Marketing Approval 1
Commitments and Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment								6,200,000			5,000,000
Further Indication for AMR101 | Potential Marketing Approval 2
Commitments and Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment								6,200,000			5,000,000
Further Indication for AMR101 | Maximum
Commitments and Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment								$ 12,300,000			£ 10,000,000