Employee Benefit Plans - Defined Contribution Plan (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Defined Contribution Plan
Defined contribution plan expenses	$ 400
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 1
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%