Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2014	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017
Concentration Risk [Line Items]
Number of common stock that can be purchased (shares)				37,840
Exercise price of warrants (in usd per share)				$ 76.11
Impairment charges						$ 0
Contract manufacturing revenue				$ 9,821,000	$ 28,525,000	$ 24,369,000
Deferred tax asset			$ 112,322,000	101,114,000	112,322,000
Less valuation allowance			112,322,000	101,114,000	$ 112,322,000
Endo Asset Purchase Agreement [Member]
Concentration Risk [Line Items]
Deferred revenue	$ 9,100,000
Term of agreement	8 years
Contract manufacturing revenue			4,900,000
Endo Asset Purchase Agreement [Member] | Minimum [Member]
Concentration Risk [Line Items]
Term of agreement	8 years
Long Lived Assets, Production [Member] | Sumavel DosePro [Member]
Concentration Risk [Line Items]
Impairment charges		$ 800,000	$ 6,400,000
ZX008 [Member]
Concentration Risk [Line Items]
Potential contingent payment, minimum				0
Potential contingent payment, maximum				$ 95,000,000.0
Accounting Standards Update 2016-09 [Member]
Concentration Risk [Line Items]
Deferred tax asset							$ 200,000
Less valuation allowance							$ 200,000
Warrants From July 2011 Debt Financing [Member]
Concentration Risk [Line Items]
Number of common stock that can be purchased (shares)				28,125
Exercise price of warrants (in usd per share)				$ 72.00
Warrants From July 2012 Public Offering [Member]
Concentration Risk [Line Items]
Number of common stock that can be purchased (shares)			1,901,918		1,901,918
Exercise price of warrants (in usd per share)			$ 20.00		$ 20.00
Term of common stock warrant exercisable					5 years