Income Taxes - Narrative (Details)	3 Months Ended			12 Months Ended			101 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 USD ($) ownership	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Aug. 31, 2006 USD ($)
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	$ 1,132,000			$ 1,132,000	$ 1,019,000	$ 899,000	$ 1,019,000	$ 714,000
Number of changes in ownership | ownership							3
Valuation allowance	96,298,000			96,298,000	110,338,000		$ 110,338,000
Income tax expense				(15,901,000)	84,000	0
Penalties and interest expense				0	0	0
Penalties and interest accrued	0			0	0		$ 0
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	177,427,000			177,427,000
Tax credit carryforward, amount	2,966,000			2,966,000
Operating loss carryforwards decrease									$ 121,100,000	$ 1,900,000
Tax credit carryforwards, decrease									3,017,000	$ 8,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Tax credit carryforward, amount	3,368,000			3,368,000
Operating loss carryforwards decrease									$ 53,329,000
State and Local Jurisdiction [Member] | California [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	181,580,000			181,580,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	20,697,000			20,697,000
Zohydro ER [Member]
Operating Loss Carryforwards [Line Items]
Tax effect of sale of discontinued operation	$ (3,472,000)	$ (5,496,000)	$ (6,946,000)	14,060,000	0	$ 0
Zogenix Europe Limited [Member]
Operating Loss Carryforwards [Line Items]
Income tax expense				$ 45,000	$ 84,000