Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) Subsidiary $ / shares shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Summary Of Significant Accounting Policies [Line Items]
Wholly-owned subsidiaries of Antares Pharma | Subsidiary		2
Carrying value of short-term investments		$ 4,993,000	$ 0
Bad debt expense		0	0	$ 0
Allowance for doubtful accounts balance		0	0
Inventory reserve		510,000	900,000
Inventory written-off		746,000	648,000
Increase in inventory reserve		356,000	748,000	700,000
Depreciation expense		1,536,000	1,326,000	1,034,000
Patent rights		3,772,000	4,659,000
Accumulated amortization of patents		2,371,000	2,614,000
Aggregate patent amortization expense, 2018		574,000
Aggregate patent amortization expense, 2019		327,000
Aggregate patent amortization expense, 2020		70,000
Aggregate patent amortization expense, 2021		57,000
Aggregate patent amortization expense, 2022		47,000
Amortization expense		568,000	534,000	536,000
Net book value of patents sold		108,000
Patent write off		46,000	0	31,000
Goodwill		1,095,000	1,095,000
Goodwill impairment loss		$ 0	0	$ 0
Cash discount to incentive for prompt payment		2.00%
Method used for fair value assumption		Black-Scholes option valuation model
Warranty period of device		24 months
Warranty liability reserves		$ 50,000	$ 100,000
Potentially dilutive securities excluded from dilutive loss per share | shares		14,761,442	13,483,856	11,151,503
Cash, cash equivalents and short-term investments		$ 31,555,000
ASU 2016-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment to accumulated deficit and additional paid-in capital		$ 97,000
Teva [Member]
Summary Of Significant Accounting Policies [Line Items]
Future net profits from commercial sales percent		50.00%
OTREXUP [Member]
Summary Of Significant Accounting Policies [Line Items]
Additional revenue recognized, not previously recognized	$ 1,297,000
Related product costs recognized	$ 254,000
Revenue Recognition, reduction in net loss		$ 1,043,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives		3 years
Capitalized cost being amortized over periods		5 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives		10 years
Capitalized cost being amortized over periods		15 years
Maximum [Member] | OTREXUP [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue Recognition, reduction in net loss per share | $ / shares		$ 0.01