Subsequent Events - Additional Information (Detail) shares in Thousands						3 Months Ended		12 Months Ended
	Feb. 23, 2017	Feb. 06, 2017 USD ($) shares	Jan. 09, 2017 USD ($) Employee	Jan. 07, 2017 USD ($) ft²	Nov. 08, 2016	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) shares
Subsequent Event [Line Items]
Restructuring activity, announcement date								Oct. 03, 2016
Restructuring expenses						$ 5,047,000	$ 809,000	$ 5,856,000
Restructuring activities, description								One-time employee termination benefits were comprised of severance, benefits and related costs, all of which resulted in cash expenditures during the third and fourth quarters of 2016.
Option grant to purchase common stock | shares								4,258
BioPharma Credit Investments IV Sub, LP (“Pharmakon”) [Member] | Credit Agreement [Member]
Subsequent Event [Line Items]
Credit facility, expiration date					Mar. 15, 2017
January 2017 Corporate Restructuring [Member]
Subsequent Event [Line Items]
Restructuring activity, announcement date								Jan. 09, 2017
Restructuring and related activities, completion date								Mar. 10, 2017
January 2017 Corporate Restructuring [Member] | One-time Employee Termination Benefits [Member]
Subsequent Event [Line Items]
Restructuring activities, description								One-time employee termination benefits are comprised of severance, benefits and related costs, all of which are expected to result in cash expenditures. The specific timing of the incurrence and payment of these restructuring expenses is dependent upon the timing of the closing of the asset sale.
Asset Sale Agreement [Member]
Subsequent Event [Line Items]
Assets sales termination fee description								The termination fee will also be payable if the Asset Sale Agreement is terminated because the Company’s stockholders did not vote to adopt the Asset Sale Agreement and, prior to such termination, a proposal to acquire at least 50% of the consolidated assets of the Company with respect to the Commercial Business or at least 50% of the Company’s voting securities has been publicly disclosed and the Company enters into a definitive agreement with respect to such proposal within 12 months after such termination, which is subsequently consummated.
Subsequent Event [Member] | BioPharma Credit Investments IV Sub, LP (“Pharmakon”) [Member] | Credit Agreement [Member]
Subsequent Event [Line Items]
Credit facility, expiration date	Apr. 27, 2017
Subsequent Event [Member] | Chief Executive Officer [Member]
Subsequent Event [Line Items]
Annual base salary		$ 700,000
Employment agreement description		Dr. Peters will receive an annual base salary of $700,000 and is eligible for an annual bonus of up to 65% of his base salary. Dr. Peters also received a one-time signing bonus of $900,000. Subject to the further approval of the Company’s Board of Directors, the Company will also grant Dr. Peters an option to purchase a number of shares of the Company’s common stock equal to the lesser of (i) such number of shares that has a target grant date fair value of $3.5 million and (ii) 2.0 million shares, with an exercise price per share equal to the fair market value of the Company’s common stock on the date of grant.
One-time signing bonus		$ 900,000
Target grant date fair value		$ 3,500,000
Option grant to purchase common stock | shares		2,000
Option vesting description		The option will vest over four years at the rate of 25% on February 6, 2018 and the remainder in equal quarterly installments over the following three years.
Subsequent Event [Member] | Chief Executive Officer [Member] | Tranche 1 [Member]
Subsequent Event [Line Items]
Options vesting period		4 years
Option vesting percentage		25.00%
Option vesting date		Feb. 06, 2018
Subsequent Event [Member] | Chief Executive Officer [Member] | Tranche 2 [Member]
Subsequent Event [Line Items]
Remainder period for vesting option		3 years
Subsequent Event [Member] | January 2017 Corporate Restructuring [Member]
Subsequent Event [Line Items]
Restructuring and related cost, number of expected employees after headcount reduction | Employee			80
Subsequent Event [Member] | Maximum [Member] | Chief Executive Officer [Member]
Subsequent Event [Line Items]
Percentage of eligible annual bonus on base salary		65.00%
Subsequent Event [Member] | Maximum [Member] | January 2017 Corporate Restructuring [Member] | One-time Employee Termination Benefits [Member]
Subsequent Event [Line Items]
Restructuring expenses			$ 8,500,000
Subsequent Event [Member] | Minimum [Member] | January 2017 Corporate Restructuring [Member] | One-time Employee Termination Benefits [Member]
Subsequent Event [Line Items]
Restructuring expenses			$ 7,500,000
Subsequent Event [Member] | Asset Sale Agreement [Member]
Subsequent Event [Line Items]
Payment of termination fee				$ 25,000,000
Minimum percentage of consolidated assets in commercial business				50.00%
Minimum percentage of voting securities				50.00%
Subsequent Event [Member] | Baxalta [Member] | License and Collaboration Agreements [Member]
Subsequent Event [Line Items]
Net milestone payments entitled to receive				$ 33,000,000
Subsequent Event [Member] | Ipsen [Member] | Asset Sale Agreement [Member]
Subsequent Event [Line Items]
Upfront cash payment to be received				$ 575,000,000
Subsequent Event [Member] | Ipsen [Member] | Asset Sale Agreement [Member] | Manufacturing Facility [Member]
Subsequent Event [Line Items]
Area of sublease property | ft²				68,409
Subsequent Event [Member] | Ipsen [Member] | Asset Sale Agreement [Member] | Maximum [Member]
Subsequent Event [Line Items]
Additional payments receivable on achievement of certain milestone events				$ 450,000,000
Out-of-pocket expenses to be paid				$ 3,000,000