Credit facilities (Details) - USD ($)	12 Months Ended	13 Months Ended
	Dec. 31, 2015	Apr. 30, 2012	Dec. 31, 2014
Line of Credit Facility [Line Items]
Required pledge of equity interests in subsidiary, percent	100.00%
Annual commitment fee	$ 125,000
Minimum
Line of Credit Facility [Line Items]
Unused commitment fee, percentage	0.30%
Maximum
Line of Credit Facility [Line Items]
Unused commitment fee, percentage	0.50%
Maxwell SA auto leases | Financing Agreements | Vehicles
Line of Credit Facility [Line Items]
Interest rate percentage, minimum	1.90%
Interest rate percentage, maximum	5.10%
Debt instrument, term	3 years
Long-term borrowings	$ 91,000		$ 82,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving line of credit, maximum	25,000,000.0
Amount available revolving credit facility	$ 22,700,000.0
Revolving Credit Facility | Prime Rate
Line of Credit Facility [Line Items]
Interest rate percentage, minimum	0.00%
Interest rate percentage, maximum	0.50%
Revolving Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Interest rate percentage, minimum	2.75%
Interest rate percentage, maximum	3.25%
Debt instrument, variable rate		2.25%
Secured Debt | Equipment Term Loan
Line of Credit Facility [Line Items]
Eligible equipment purchase, percentage		80.00%
Debt instrument, amount borrowed		$ 5,000,000