Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Mar. 25, 2019	Jun. 29, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Alphatec Holdings, Inc.
Entity Central Index Key	0001350653
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Trading Symbol	ATEC
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding		46,847,652
Entity Public Float			$ 70.2
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Shell Company	false