Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities
Net loss	$ (27,354)	$ (27,790)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	962	824
Change in fair value of warrant liabilities	0	4
Stock-based compensation	5,600	5,540
Increase (decrease) in cash resulting from changes in:
Accounts receivable	(527)	(771)
Grants receivable	(260)	0
Inventory	(55)	6
Prepaid expenses and other assets	253	400
Accounts payable	(719)	(65)
Accrued expenses	(1,293)	486
Deferred rent	(113)	(103)
Deferred revenue	260	(490)
Net cash used in operating activities	(23,246)	(21,959)
Cash Flows From Investing Activities
Restricted cash deposits	0	(48)
Purchases of fixed assets	(90)	(1,061)
Purchases of intangible assets	(70)	0
Net cash used in investing activities	(160)	(1,109)
Cash Flows From Financing Activities
Proceeds from issuance of common stock and exercise of warrants, net	7,169	30,401
Proceeds from exercise of stock options	826	582
Net cash provided by financing activities	7,995	30,983
Effect of currency exchange rate changes on cash and cash equivalents	(2)	(10)
Net Increase (Decrease) in Cash and Cash Equivalents	(15,413)	7,905
Cash and Cash Equivalents at Beginning of Period	62,751	62,091
Cash and Cash Equivalents at End of Period	47,338	69,996
Supplemental Disclosure of Cash Flow Information:
Interest paid	0	0
Income taxes paid	$ 0	$ 23