Employee Benefit Plans - Defined Contribution Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan
Employer contributed by eligible participants	50.00%
Defined contribution plan expenses	$ 400,000	$ 400,000
Maximum
Defined Contribution Plan
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 1,200	$ 1,000
Regular employees
Defined Contribution Plan
Maximum contribution per employee under the Axcelis Long-Term Investment Plan (as a percent)	35.00%
Highly compensated employees
Defined Contribution Plan
Maximum contribution per employee under the Axcelis Long-Term Investment Plan (as a percent)	16.00%