Note 4. Inventory

Our inventory balance consists of the following:


	December 31,
	2015		2014
	(in thousands)

Raw materials	$	—	$	591
Work-in-process		17,555		18,487
Finished goods		1,783		358
		19,338		19,436
Inventories-current		1,783		358
Inventories-non-current	$	17,555	$	19,078

Inventories, stated at the lower of cost or market, consist of raw materials, work in process and finished goods. At December 31, 2015, $1.8 million of inventory was classified as current on the consolidated balance sheets as we expect this inventory to be consumed for commercial use within the next twelve months. At December 31, 2015, $17.6 million of inventory was classified as non‑current on the consolidated balance sheets as we did not expect this inventory to be consumed for commercial use within the next twelve months. We obtain some inventory components from a limited number of suppliers due to technology, availability, price, quality or other considerations. The loss of a supplier, the deterioration of our relationship with a supplier, or any unilateral violation of the contractual terms under which we are supplied components by a supplier could adversely affect our total revenues and gross margins.

The raw materials and work‑in‑process inventory is not subject to expiration and the shelf life for finished goods inventory is 36 months from the start of manufacturing of the finished goods. We evaluate for potential excess inventory by analyzing current and future product demand relative to the remaining product shelf life. We build demand forecasts by considering factors such as, but not limited to, overall market potential, market share, market acceptance and patient usage.