Stock-Based Awards

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

The Company grants stock-based awards under its 2017 Stock Option and Incentive Plan (the 2017 Plan) and is authorized to issue common stock under its 2017 Employee Stock Purchase Plan (ESPP). The Company also has outstanding stock options under its 2015 Equity Incentive Plan but is no longer granting awards under this plan. As of March 31, 2020, 1,878,252 shares of common stock were available for issuance under the 2017 Plan. As of March 31, 2020, 1,409,433 shares of common stock were available for issuance to participating employees under the ESPP.

Stock-based compensation expense was classified in the statements of operations and comprehensive loss as follows:


	Three Months Ended March 31,
(in thousands)	2020		2019
Research and development expenses	$	3,271	$	1,692
Selling, general, and administrative expenses	3,723		4,537
Total stock-based compensation	$	6,994	$	6,229

As of March 31, 2020, total unrecognized compensation cost related to the unvested share-based awards was $102.4 million, which is expected to be recognized over a weighted average of 2.9 years. During the three months ended March 31, 2019, the Company recorded $2.4 million of stock-based compensation expense related to the modification of stock options pursuant to the transition agreement with its former President and Chief Executive Officer.