We have one operating segment based on how management internally evaluates separate financial information, business activities and management responsibility.

Revenue is disaggregated as follows:


	Three months ended				Six months ended
	June 30,				June 30,
	2022		2021		2022		2021
Product sales	$	334,113	$	1,953	$	502,240	$	24,000
Contract revenue 1		2,989,614		545,547		5,696,182		954,467
Other development revenue		—		76,820		100,000		242,156
Development revenue		2,989,614		622,367		5,796,182		1,196,623
	$	3,323,727	$	624,320	$	6,298,422	$	1,220,623

1 A portion of contract revenue represents previously recorded deferred revenue that was recognized as revenue after satisfaction of performance obligations either through passage of time or after completion of specific performance milestones.

A significant amount of our revenue is derived from contracts with major customers. For the three and six months ended June 30, 2022, revenue from one customer accounted for $3.2 million or 97% and $5.9 million or 94% respectively of total revenue. We currently derive a significant portion of our revenue from contract services with a G10 central bank. In 2021, we acquired a development contract for up to $41.5 million over a period of up to five years. These contract services incorporate both nano-optic and optical thin film technologies and are focused on developing authentication features for future banknotes.

For the three and six months ended June 30, 2021, we had one customer that accounted for $377,637 or 60% and $622,866 or 51% respectively of total revenue.